How to Write Alt Text for Images People Actually Need

Here’s how to write alt text for images in one breath: describe what the image shows and why it matters in this context, in about a sentence, as if you were describing it over the phone to a friend who can’t see the screen. Be specific, skip “image of,” state the finding if it’s a chart, and leave the alt attribute empty — alt=”” — if the image is purely decorative. Write it for people first; the search benefit follows on its own.

Okay, let’s be honest about something: most of us learned about alt text from an SEO checklist. “Add alt tags for rankings!” And so the web filled up with images labeled best-crm-software-2024-top-tools — which helps exactly no one. Here’s the reframe I want to give you, because it changes everything downstream: alt text is how a real person, using a screen reader, experiences your images. Your words are the image for them. When you write alt text as an act of description for a human being, you write better alt text — and, happily, that’s also exactly the kind search engines reward. People first. SEO follows.

What is alt text, and who is it actually for?

Alt text (alternative text) is the written description attached to an image — the alt attribute in HTML, the “alt text” field in your CMS, the accessibility description on social platforms. It’s what gets read aloud by screen readers, what displays if an image fails to load, and what search engines read to understand what your image contains.

But let’s put the audiences in their honest order, because the order is the whole philosophy:

• Blind and low-vision readers using screen readers. This is the primary audience, full stop. When a screen reader reaches your image, it reads your alt text aloud. If you wrote “chart,” they hear “chart” and nothing more. If you wrote nothing, many screen readers fall back to reading the file name — imagine hearing “IMG underscore four seven three two dot jpeg” in the middle of an article you were enjoying. Your alt text is the difference between being included in the content and being locked out of part of it.
• Anyone whose image didn’t load. Slow connections, blocked images in email, broken links — the alt text displays in the image’s place and keeps the content intact.
• Search engines. Yes, alt text helps crawlers understand images, which supports image search and gives your page clearer context. That benefit is real. It’s also the last reason on the list, and here’s the lovely part: writing genuinely descriptive alt text for people is the exact behavior that produces good image SEO. There is no conflict. The accessible version and the optimized version are the same sentence.

So for the rest of this guide, we’re writing for the person listening. Everything else comes along for free.

How do you write alt text for images? The core craft rules

Good alt text comes down to a handful of habits. None of them is hard; together they’ll put you ahead of most of the web.

Describe what matters in this context

This is the rule that separates thoughtful alt text from mechanical alt text: the same image needs different alt text depending on where it appears. Alt text doesn’t describe the image in the abstract — it describes the job the image is doing right here.

Picture a photo of a woman working on a laptop in a coffee shop. In an article about remote work, the alt text might be “Freelancer working on a laptop at a sunlit coffee shop table.” In an article about laptop ergonomics, the same photo might be “Woman hunched over a laptop at a low café table, shoulders rounded — the posture most remote workers default to.” Same pixels, different job, different words. Before you write, ask: what is this image adding to this moment in this piece? Then describe that.

Be specific — and stop at about a sentence

Two vague words (“team photo”) underserve the listener; a three-paragraph essay overserves them. The sweet spot is a focused sentence, give or take — enough to carry the image’s meaning, short enough to listen to comfortably. “Dog” is too thin. “Golden retriever puppy mid-leap catching a frisbee on a beach” is a picture in words. If you find yourself writing multiple sentences, that’s usually a sign the image carries more information than alt text should hold — we’ll handle that in the infographics section below.

Convey the information or the feeling — whichever the image is there for

Some images carry data; describe the data. Some images carry mood; describe the mood. A hero photo chosen to feel calm and spacious can honestly be described as “Minimalist desk with a single notebook and a cup of coffee in soft morning light” — the atmosphere is the content. Don’t strip the warmth out of your descriptions in pursuit of efficiency. The listener deserves the feeling of the page, not just its inventory.

Skip “image of” and “picture of”

Screen readers announce images as images before reading your alt text. If you write “Image of a bar chart,” the listener hears “Image: image of a bar chart.” Just start describing: “Bar chart comparing…” The one nuance worth keeping: if the format is meaningful, name it — “Watercolor illustration of…” or “Screenshot of…” tells the listener something real about what kind of thing they’re not seeing.

End with punctuation

A small kindness that costs nothing: end your alt text with a period. Many screen readers use it to pause naturally before moving on, so the description ends like a sentence instead of crashing into the next element. Tiny detail, more humane listening experience.

How do you write alt text for different image types?

Knowing how to write alt text for images in general is half the skill; the other half is adapting it per type. The core rules hold everywhere, but each image type has its own version of “what matters.” This is where alt text goes from adequate to genuinely good.

Photos

Describe who or what is in the frame and the mood or action, as relevant to your context. Identify people by name if their identity matters (“Maya Chen presenting at the company retreat”) and by relevant description if it doesn’t (“Two colleagues reviewing a printed report together”). Don’t inventory every background object — describe what the photo is for.

Screenshots

Here’s the trap with screenshots: describing everything visible. A screenshot of an app contains dozens of elements, and a listener does not need all of them. Describe what the reader is supposed to notice: “The Settings menu with Notifications highlighted.” “The post composer with the schedule button in the lower right.” Your alt text should answer the question the screenshot was answering. If your tutorial says “click here,” the alt text should tell the listener where “here” is.

Charts and graphs

This is my favorite rule in the whole discipline, because it forces honesty: state the finding. “Chart” tells the listener nothing. “Line chart of signups” tells them the format but withholds the point. “Line chart showing signups rising steadily from January to June” delivers what the sighted reader got at a glance — the takeaway.

And notice the quiet integrity check hiding in there: if you can’t state your chart’s finding in one honest sentence, maybe the chart doesn’t show what you’ve been implying it shows. Writing alt text for your own data is a tiny audit of your own claims. State what the data actually shows — no rounding up, no spin — and your alt text and your credibility both come out stronger.

Infographics

An infographic is the one image type that legitimately holds more information than alt text should carry. Don’t try to cram ten statistics into the alt attribute. Instead, do one of two things: summarize the infographic’s main takeaway in the alt text (“Infographic summarizing the five stages of a content audit, from inventory to rewrite”), or — better for dense ones — provide the full content as text on the page or a linked text version, and let the alt text say so: “Infographic of the 12-step publishing checklist; full text version below.” The pattern is called a long description, and it’s the honest answer to “this image is really a document.” If you maintain a resource page for your best material, text versions of your infographics belong there too — they make the content accessible and linkable.

Product images

Describe what a shopper would want to know from looking: the item, its color, material, angle, and any detail the photo exists to show. “Navy canvas tote bag with brown leather straps, shown from the front.” If you have six photos of the same product, differentiate them — “close-up of the interior zip pocket” — instead of repeating the product name six times.

Decorative images: the counterintuitive rule

Here’s the one that surprises people: for purely decorative images, the correct alt text is empty — alt=””. Not a description. Not the file name. Deliberately, explicitly empty.

A decorative divider, a background flourish, an abstract shape that exists only to make the page prettier — these add nothing a listener needs. An empty alt attribute tells the screen reader “skip this,” and the listener glides past without interruption. Describing it (“purple wavy line divider”) forces them to sit through noise. And omitting the attribute entirely is worse than empty, because many screen readers then read the file name aloud. Silence beats noise — but it has to be deliberate silence.

The test: if the image vanished, would the reader lose any information or meaning? No? Then alt=”” and move on, guilt-free. Yes? Then it’s not decorative, and it earns a description.

What should you never do with alt text?

Three habits to break on sight — your own, or the ones you inherit in an audit.

Keyword stuffing

Alt text like “best social media scheduler social media tool scheduling software 2025” is a double offense. To the screen-reader user, it’s gibberish read aloud — an accessibility insult, honestly, because it treats their reading experience as a slot for your keywords. And to search engines, it’s a classic spam signal that can hurt the page rather than help it. There is no version of this that works. If your keyword belongs in an image’s honest description, it’ll appear naturally; if it doesn’t, forcing it in costs you twice.

Repeating the caption verbatim

If your image has a visible caption, the screen reader will read it. Alt text that duplicates it word-for-word means the listener hears everything twice. Captions and alt text have different jobs (more on that in a moment) — when both exist, make the alt text cover what the caption doesn’t: the visual description.

Leaving auto-generated alt text unreviewed

Plenty of platforms and AI tools now generate alt text automatically, and as a starting point, that’s genuinely useful — far better than the empty attributes of a decade ago. But auto-generated descriptions miss context by definition: the tool sees pixels, not your article. It will describe your conversion-funnel chart as “a colorful diagram” and your pointed screenshot as “a computer screen with text.” Treat machine-generated alt text as a draft, never a deliverable. Review it, add the context, state the finding. The thirty seconds you spend is the entire difference.

Where does alt text live across your platforms?

Once writing alt text is a habit, the next question is where to apply it. The answer: everywhere your images go.

Your website and CMS

Every major CMS has an alt text field in the media library or image settings — WordPress, Webflow, Shopify, Squarespace, all of them. The habit to build: fill the field when you upload, not “later.” One caution for template-driven sites: an alt text set in a media library may follow the image everywhere it’s reused, which collides with the context rule. When an image does a different job on a different page, override the alt text at the placement level if your platform allows it.

Social platforms

Here’s something that still surprises people: most major social platforms have alt text fields for images — they’re just tucked away where only the thoughtful find them. Using them is both kind and professional: your social audience includes screen-reader users too, and they deserve more than “image” where your carefully chosen visual should be.

The practical problem is remembering, in the rush of posting, to open the accessibility option and write the description. The fix is workflow, not willpower: make alt text part of composing the post, not an afterthought. If you schedule your content ahead of time, write the alt text in the same sitting as the caption — in SocialBlaze’s composer, you can add alt text to your images as you schedule, so every post that goes out across your networks carries its description with it. Batch the kindness along with the content.

Email

Email is where alt text quietly earns double wages, because many email clients block images by default. Your alt text is what subscribers see in place of every blocked image — which means an image-heavy email with no alt text can arrive as a field of empty gray boxes. Describe your images, and your email still communicates even before anyone clicks “display images.” For buttons built as images, make the alt text the action: “Get the free template.”

What’s the difference between captions and alt text?

These two get conflated constantly, so let’s give each its job description.

A caption is visible context for everyone. It appears under the image and adds commentary, attribution, or interpretation that sighted and non-sighted readers alike benefit from: “Our booth at last spring’s conference — the banner survived three flights.” A caption assumes you can see the image and adds to it.

Alt text is a non-visual substitute for the image itself. It replaces the visual experience for someone who isn’t getting it: “Trade show booth with a purple banner reading ‘Social Blaze’ above a table of demo laptops.” Alt text assumes you can’t see the image and stands in for it.

Different jobs, both worth doing. A well-dressed image can have both: alt text that describes the visual, a caption that interprets it. What it shouldn’t have is the same sentence in both slots — that’s the duplication problem from earlier. And neither one is the place for your photo credit metadata or your keyword list; those have their own homes.

How do you build alt text into your content workflow?

The difference between sites with good alt text and sites without it is almost never knowing how to write alt text for images — it’s workflow. Here’s how to make it automatic.

Write alt text at creation time, not as a retrofit

The moment you place an image is the moment you know exactly why it’s there — which, per the context rule, is exactly what the alt text should say. Write it then. It takes thirty seconds while the context is in your head, versus a painful archaeology session months later when someone asks “what was this chart even showing?” Alt text written at creation time is better and cheaper. This is the same logic that applies to structure generally — just as it’s easier to fix your heading hierarchy while drafting than after publishing (if you’re tightening that up too, my guide to writing better subheadings covers how screen-reader users navigate by headings), accessibility is cheapest when it’s part of the build.

Add alt text to your publishing checklist

Every piece of content you publish should pass through a short image check before it goes live:

• Every informative image has alt text — specific, contextual, about a sentence.
• Every chart’s alt text states the finding, honestly.
• Every screenshot’s alt text names what the reader should notice.
• Every decorative image has an explicitly empty alt=”” — not a missing attribute.
• No alt text starts with “image of” or “picture of.”
• No alt text duplicates a visible caption verbatim.
• Any auto-generated alt text has been reviewed and contextualized by a human.
• Dense infographics have a text version on the page or linked nearby.
• Social versions of the post have alt text in the platform’s accessibility field.

Pin that list where you draft. Checklists work precisely because they don’t rely on memory on a busy day — and if your team runs on printed or shared checklists, this one is a perfect candidate for your printable resources library, taped next to the monitor of everyone who publishes.

Audit existing content gradually — top pages first

If you have years of published content with thin or missing alt text, do not try to fix it all in a weekend. You’ll burn out by Sunday and resent every image you own. Audit gradually, highest-impact first:

• Step 1: List your top pages. Pull your most-visited pages from analytics — these are where missing alt text affects the most real readers. Start with the top ten.
• Step 2: Check every image on each page. Browser accessibility checkers and most SEO crawlers will flag images with missing alt attributes. For each image, note: missing, vague, stuffed, or fine.
• Step 3: Fix in place with fresh context. Rewrite each flagged image’s alt text using the rules above — reading the surrounding paragraph first, because context decides the words.
• Step 4: Mark true decoratives as empty. You’ll find plenty of dividers and flourishes carrying junk descriptions. Set them to alt=”” and enjoy how much quieter the page just got for listeners.
• Step 5: Batch by ten. Ten pages per week, every week, and the backlog resolves itself in a season — while your new content, per the workflow above, never adds to it.

What does good alt text look like? Weak-to-strong rewrites

Theory becomes skill through examples. Here’s one weak-to-strong rewrite for each image type — notice how every “strong” version answers what matters in context:

• Photo — Weak: “woman laptop” → Strong: “Freelancer sketching a content calendar in a notebook beside her laptop, coffee in hand.”
• Screenshot — Weak: “screenshot of the app” → Strong: “The scheduling screen with the ‘best time to post’ suggestion highlighted above the calendar.”
• Chart — Weak: “graph” → Strong: “Line chart showing email signups rising steadily from January to June after the resource page launched.”
• Infographic — Weak: “content marketing infographic” → Strong: “Infographic summarizing the five-step image audit workflow; full text version linked below.”
• Product image — Weak: “tote-bag-final-v2.jpg” (file name as alt) → Strong: “Navy canvas tote with brown leather straps, interior zip pocket shown open.”
• Decorative — Weak: “purple gradient wave divider graphic” → Strong: alt=”” — nothing at all, on purpose.

Read the strong column aloud and you can hear the difference: each one would make sense, and carry real information, to someone listening with their eyes closed. That’s the test that matters.

Your alt text cheat sheet by image type

Bookmark this table — it’s the whole article in one glance:

Image type	What the alt text should do	Shape of a good one
Photo	Convey who/what and the relevant mood or action	“Two colleagues reviewing a printed report at a standing desk.”
Screenshot	Name what the reader should notice	“The Settings menu with Notifications highlighted.”
Chart/graph	State the finding, honestly	“Bar chart showing most replies arriving within the first hour after posting.”
Infographic	Summarize the takeaway; link or include a text version	“Infographic of the 12-step publishing checklist; full text below.”
Product image	Describe what a shopper is looking for in this shot	“Close-up of the tote’s interior zip pocket.”
Decorative	Stay silent — deliberately	alt=”” (empty, never omitted)

One last warm nudge before the questions: alt text is one of those rare practices where the right thing and the smart thing are the same thing. Every description you write makes your content genuinely usable for more people — and every one of them also makes your images legible to search engines, your emails readable with images blocked, and your own claims about your charts a little more honest. Few habits pay that many audiences at once for the price of one sentence.

FAQ: how to write alt text for images

How long should alt text be?

Aim for about a sentence — long enough to carry what the image means in context, short enough to listen to comfortably. Two vague words underserve the listener; multiple paragraphs belong in a text version on the page, not in the alt attribute.

Should decorative images have alt text?

No — purely decorative images should have an explicitly empty alt attribute (alt=””), which tells screen readers to skip them. Don’t omit the attribute entirely, though: many screen readers then read the file name aloud, which is worse than silence.

Does alt text help SEO?

Yes — alt text helps search engines understand your images, supports image search, and adds context to the page. But keyword-stuffed alt text hurts both rankings and readers. Write a genuinely descriptive sentence for the listener, and the SEO value comes along naturally.

What’s the difference between alt text and a caption?

A caption is visible context for everyone — commentary or attribution displayed under the image. Alt text is a non-visual substitute for the image itself, read by screen readers in its place. They have different jobs, so they shouldn’t duplicate each other word-for-word.

How do you write alt text for a chart or graph?

State the finding, not just the format: “Line chart showing signups rising steadily from January to June” gives a listener what a sighted reader gets at a glance. Describe what the data honestly shows — if you can’t summarize the finding in a sentence, the chart may need rethinking too.