Image Alt Text Generator

Practical guide: alt text that helps humans and search

What this is

Alt text is an HTML attribute on <img> (or equivalent ARIA patterns) describing the informative content of an image. Screen readers read it aloud; search engines use it when image understanding matters; browsers show it when the asset fails. Decorative visuals should carry empty alt so assistive tech skips them. Alt is accessibility first; SEO benefit is a side effect of clarity, not a place to stash keywords.

When to invest in better alt

• Product photos that convey color, model, or material users cannot get from the filename.
• Charts, diagrams, and screenshots that carry meaning beyond “illustration.”
• Functional icons and buttons where the image is the only label.
• After an accessibility audit flags missing or filename-as-alt attributes.
• As part of content QA alongside readability and hygiene—see the SEO guide and technical hygiene checklist.

When empty or minimal alt is correct

• Purely decorative borders, spacers, and mood backgrounds that add no information.
• Images already described fully by an adjacent visible caption—avoid doubling long text unless the caption is insufficient alone.
• Repeated logos in footers when the link has accessible link text already (context matters—homepage logo links often need “Company home”).
• Do not empty alt on product or instructional images just to “look clean” in an SEO crawl report.
• Never use alt as a dumping ground for every target keyword on the page.

How to use this tool

Describe what matters about the image in context of the surrounding paragraph—same photo can merit different alt on different pages. For functional images (buttons, icons with meaning), state the action (“Search,” “Download PDF”). For charts, summarize the insight, not only “graph of sales.” Keep length reasonable; long alt is still better than silent charts for blind users, but put extended detail in visible caption text when needed.

Worked example

Blog post comparing two espresso machines. Hero photo: side-by-side machines on a counter. Weak alt: alt="SEO coffee espresso best machine 2026 buy now". Better alt: alt="Stainless PortaPro 500 beside compact HomeBrew Mini on a wooden counter". Infographic of brew temperature ranges: alt summarizes “PortaPro holds 93°C; HomeBrew Mini ranges 88–92°C” while a visible caption expands methodology. Decorative steam swirl in the sidebar: alt="". After publish, an accessibility pass confirms decorative images are skipped and product shots remain descriptive. Keyword clustering for the article lives in headings and body—not in alt stuffing (clustering without stuffing).

How to read the results

If this tool suggests shorter phrasing, check for redundant “image of” openers or duplicated nearby text. Keyword suggestions should read naturally; alt is not a hidden SEO stash. Empty alt recommendations apply only when the image truly adds no new information—do not empty alt on product photos that carry model, color, or text users rely on.

Common mistakes

• Stuffing keywords into every icon and thumbnail.
• Copying filenames like IMG_0001.jpg as alt.
• Leaving meaningful images with missing alt attributes.
• Using identical alt for every thumbnail in a gallery.
• Replacing structured captions with alt-only content sighted users never see.
• Writing novels in alt when a short description plus caption would serve everyone better.

QA checklist for image alt

1. Informative images have concise, accurate alt in the user’s language.
2. Decorative images use empty alt (alt=""), not missing attributes.
3. Functional images describe the action or destination.
4. No keyword lists, no “image of…” boilerplate unless needed for clarity.
5. Gallery items differ when the visuals differ; avoid copy-paste alt.
6. Spot-check with a screen reader or accessibility tree on key templates.

Related reading

SEO guide · Technical hygiene · Keyword clustering without stuffing · Helpful vs spammy schema (for ImageObject care). Related tools: content optimization tools, readability checker, SEO audit.

Before / after: gallery copy-paste alt

Before: A lookbook gallery reused alt="summer collection fashion" on twenty distinct outfits. Screen reader users heard the same phrase repeatedly; image search gained little unique signal.

After: Each shot described garment, color, and notable detail (“navy linen blazer over white tee, rolled sleeves”). Decorative divider images switched to empty alt. Editors got a one-line style guide in the CMS. Accessibility scores and image query relevance both improved without keyword stuffing.

Alt, captions, and surrounding text

Alt should not duplicate a long caption verbatim if that creates noisy repetition for screen reader users—summarize in alt and keep detail visible. Conversely, do not hide essential meaning only in a caption that some themes fail to associate programmatically. Test a key template with a screen reader after theme changes; visual QA alone misses broken relationships between figure, caption, and alt.