Image Alt Checker — Find Every Missing Alt Text on Any Web Page

Image alt text is one of the most consistently neglected SEO elements

Alt text is the written description of an image that appears when the image fails to load and is read aloud by screen readers. It's also how search engines understand what an image contains — since they can't see the image itself. Despite being a basic SEO requirement, a large percentage of images on most websites are missing alt text entirely.

An image alt checker scans a URL and reports every image found — showing which ones have alt text, which are missing it, and what the existing alt text says.

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What Image Alt Text Does

Alt text serves three purposes:

1. Accessibility. Screen readers used by visually impaired users read alt text aloud, allowing them to understand what an image depicts. Without alt text, they hear "image" or the filename — not useful. WCAG accessibility guidelines require meaningful alt text for all informational images.

2. SEO. Search engines use alt text to understand image content, which influences:

• Image search rankings — images with relevant alt text appear in Google Images for related queries
• Page relevance signals — images with keyword-relevant alt text reinforce the page's topical relevance
• Crawl efficiency — descriptive alt text gives search engines more context about page content

3. Fallback display. When an image fails to load (slow connection, broken image URL), the alt text is displayed in its place — maintaining content comprehension.

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What Good Alt Text Looks Like

Descriptive and specific:

• Bad: alt="image"
• Bad: alt="photo"
• Bad: alt="IMG_20240115_142305.jpg" (filename)
• Good: alt="EMI calculator showing loan repayment breakdown for a ৳5 lakh home loan"

Contextually relevant: Alt text should describe what the image shows in the context of the surrounding content — not just generically describe the image in isolation.

Naturally includes keywords where appropriate:

• Bad (keyword stuffing): alt="best EMI calculator online free EMI calculator Bangladesh loan calculator"
• Good: alt="Free EMI calculator interface with fields for loan amount, interest rate, and tenure"

Decorative images use empty alt text: Purely decorative images (dividers, background textures, purely stylistic icons) should have alt="" — an empty alt attribute — not a description. This tells screen readers to skip the image. Without any alt attribute, screen readers read the filename, which is worse.

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How to Use the Image Alt Checker on sadiqbd.com

1. Enter the URL — the web page you want to audit
2. Run the check — the tool fetches the page and identifies all <img> tags
3. Read the results:
   • Images with alt text — shown with their alt text content
   • Images missing alt attribute entirely — flagged as errors
   • Images with empty alt text (alt="") — noted separately (potentially intentional for decorative images)
   • Images with generic alt text (like "image" or the filename) — flagged for improvement

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Real-World Examples

New page audit before publishing

A product page has 8 images. The alt checker returns:

• 3 images: ✓ has descriptive alt text
• 3 images: ✗ missing alt attribute entirely
• 2 images: ⚠ alt text is filename (e.g. product-photo-1.jpg)

Fix before publishing: write descriptive alt text for the 5 problematic images.

Accessibility audit for a business website

The alt checker on the homepage reveals:

• Logo: alt="" — empty alt, correct for a decorative image (unless it's the only branding element, in which case alt="Company Name" is better)
• Hero image: alt="hero" — too generic, needs rewriting
• Team photo: missing alt — needs alt="The Example Company team at our Dhaka office"
• Icon images in feature list: alt="" — acceptable if the feature name appears in adjacent text

Product catalogue with hundreds of images

An e-commerce store runs the checker on its product category page. Many product thumbnail images show:

alt="product-thumb-id-4829.webp" — auto-generated filenames used as alt text

This is a common CMS default. The fix: ensure the product image upload field requires alt text, and retroactively update existing images with descriptive text including the product name and key feature.

Checking competitor image optimisation

Running the alt checker on a competitor's page reveals they have detailed, keyword-rich alt text on every product image while yours are mostly empty. This gap is partially explaining why their images appear in Google Images searches for relevant terms.

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Alt Text for Different Image Types

Product images: Include the product name, colour, and key attribute. alt="Blue cotton kurta for men — regular fit, size M".

Infographics: Describe the key information conveyed, not just "infographic." alt="Bar chart showing EMI comparison for ৳10 lakh loan at different interest rates from 8% to 14%"

Screenshots: Describe what's shown in the interface. alt="sadiqbd.com EMI Calculator showing result panel with monthly payment, total interest, and amortisation table"

Logos: Use the company/brand name. alt="sadiqbd.com logo"

Team/person photos: alt="Sadiqur Rahman, software developer and founder of sadiqbd.com"

Decorative images: alt="" (empty — screen readers skip)

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Alt Text Length

There's no hard limit, but practical guidance:

• Keep it concise — 125 characters is a commonly cited soft limit (screen reader behaviour varies beyond this)
• Include the most important descriptive information within the first 80–100 characters
• Don't write paragraphs — alt text is a brief description, not a caption

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Tips for Image Alt Text Optimisation

Write alt text for the image in context, not the image in isolation. A photo of a laptop on a page about developer tools has different alt text than the same photo on a page about physical product reviews. Context shapes meaning.

Don't start with "Image of..." or "Photo of..." Screen readers already announce it's an image. Start with the description directly.

For complex images (charts, diagrams), provide a text summary nearby. Alt text has length limits; a data table or paragraph near the image can provide full information while alt text gives a brief overview.

Use your CMS image alt field consistently. WordPress, Shopify, and most CMS platforms have dedicated alt text fields. Fill them in at upload time — it's easier than retroactively updating hundreds of images.

Batch audit regularly. New images are added constantly. A recurring monthly or quarterly audit using the checker catches accumulating gaps.

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Frequently Asked Questions

Do all images need alt text? Informational images (those that contribute meaning to the page) need descriptive alt text. Decorative images (purely visual, adding no meaning) should have empty alt (alt=""). No image should lack the alt attribute entirely — that's the worst outcome for accessibility.

Does alt text directly affect page rankings? Not as a standalone factor, but it contributes to topical relevance signals, affects image search visibility, and is part of overall on-page optimisation quality. Its most direct impact is on image search rankings.

Can I use the same alt text for duplicate images? If identical images appear on multiple pages in different contexts, tailor the alt text to the context. If the same image appears twice on the same page (which should be avoided), the alt text should be the same.

What about SVG images and CSS background images? SVG images in HTML <img> tags need alt text like any other image. SVG images inline in HTML can use aria-label or <title> for accessibility. CSS background images aren't announced by screen readers — use <img> with alt text for informational images.

Is the image alt checker free? Yes — completely free, no sign-up needed.

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Image alt text is fast to write, easy to implement, and consistently overlooked. The checker surfaces every gap on a page in one pass — so fixing it requires only the writing, not the hunting.

Try the Image Alt Checker free at sadiqbd.com — find every image on any page and see which ones are missing alt text.