Alt text — the alt attribute for images — describes image content for screen readers and search engines. Without quality alt descriptions, a page loses visibility in image search, may rank lower in regular search results, and becomes inaccessible to users with disabilities. Writing alt text manually for hundreds of images takes hours. AI-generated alt text can automate this process without sacrificing quality. This article explains why alt text matters, how AI vision models work, and which practices to use when automating.
Why alt text matters for SEO and accessibility
| Purpose | Description |
|---|---|
| Accessibility | Screen readers read alt text instead of the image — without it, the image is “silent” to users with visual impairments |
| Image search | Google Images indexes alt text and uses it to rank images in search results |
| Page context | Search engines use alt text to understand the topic and relevance of content |
| Fallback | When images are disabled or load slowly, the alt text is displayed |
According to WCAG 2.1, every meaningful image must have a text alternative. Decorative elements — alt="". Ignoring alt text can lead to lost traffic from Google Images and non-compliance with accessibility requirements.
For online stores, product images are the primary content. Without alt text, a catalog of thousands of products remains invisible to image search. For blogs and media sites, alt text helps index infographics, screenshots, and illustrations. For corporate websites, it applies to photos of teams, offices, and products. In each case, alt text turns visual content into a text signal for search engines and assistive technologies.
How AI vision models generate alt text
Modern multimodal models (GPT-4 Vision, Claude with image support, Gemini) analyze an image and generate a text description. The process includes:
- Object recognition — people, items, scenes, and text in the image
- Context understanding — actions, emotions, and surroundings
- Description generation — concise, informative text in the specified format
The model receives an image and a prompt such as: “Describe this image for the alt attribute. Up to 125 characters. Include key objects and context. Do not use the words ‘image,’ ‘picture,’ or ‘photo.’” The result is ready-to-use alt text that can be inserted into HTML.
AI advantages include speed (seconds per image), consistent style, and the ability to process images in bulk. Limitations: the model may miss important details or overestimate or underestimate the importance of elements. Editorial review is still essential.
For batch processing, it is important to specify a consistent style in the prompt: “Use the format: [object] + [characteristics] + [context].” This ensures consistency across the entire catalog. For products, specify whether to include the brand, model, and color—the model will take this into account when generating the text.
Best practices for alt text
Optimal length
Google usually truncates alt text longer than 125 characters. The recommended range is 80–125 characters. This is enough to describe the content without overloading the snippet.
Describe the content, not the format
<!-- Плохо -->
<img src="product.jpg" alt="Прямоугольное изображение товара">
<!-- Хорошо -->
<img src="product.jpg" alt="Беспроводные наушники Sony WH-1000XM5 чёрного цвета на белом фоне">Include keywords naturally
The keyword should fit naturally into the description rather than look like an insertion. Keyword stuffing harms both SEO and readability for screen reader users.
Decorative images — empty alt text
Icons, dividers, and decorative backgrounds — alt="". Screen readers will skip them, which is appropriate.
Uniqueness
Each image should have unique alt text. Reusing the same description for multiple images is a mistake.
Image types: alt text specifics
For product photos, include the name, brand, key characteristics (color, model), and, if necessary, the shooting context. For infographics, briefly summarize the data and conclusions. For screenshots, describe what is shown on screen and why. For photos of people, describe the action and context, and include names if necessary (with consent). For logos, use “Logo of [company name].” For linked images, describe the link destination: “Go to the smartphone catalog.”
Templates based on file names (product-123.jpg → “Product 123”) produce weak results. Descriptive file names help, but they do not replace full alt text. AI analyzes visual content, which provides a fundamentally different level of information. Combine CMS data (name, SKU) with an AI-generated scene description for better results. When integrating with WordPress, Bitrix, or other CMS platforms, check whether the plugin or module supports bulk alt text import—this will make large-scale updates easier. Regular image audits with the reChecker image analyzer will show pages with missing or weak alt text—prioritize them for improvement.
AI Alt Generator tool
To generate alt text automatically, you can use the reChecker AI Alt Text Generator. The service analyzes images with a vision model and creates SEO-optimized descriptions. Batch uploads are supported, which is convenient for product catalogs and galleries. You can copy the results into a CMS or export them. It is recommended that you review generated alt text before publishing and edit it if necessary.
Workflow: upload images, provide context if needed (product category, page topic), and get a list of alt texts. Review 10–20% of the results, especially for top pages. Add them to the CMS by copying them or using the API. Review alt text periodically when updating the catalog or changing your SEO strategy.
Pre-publication checklist
| Check | Action |
|---|---|
| Length up to 125 characters | Shorten long descriptions |
| Keywords used naturally | Remove keyword stuffing |
| Uniqueness | Use different alt text for different images |
| Decorative images — alt="" | Check icons and dividers |
| Specificity | Replace generic wording (“product,” “photo”) |
Frequently asked questions
Can I trust AI-generated alt text completely?
AI provides a good starting point, but a final human review is recommended. The model may get details wrong (such as a product’s color or model) or miss important context. This is especially true in specialized niches such as medicine, technology, and jewelry.
How does AI process images with text?
Vision models can recognize text in an image (OCR) and include it in the alt text. This is useful for infographics and screenshots, as key text appears in the description. Check that the extracted text is accurate and relevant.
Do images in CSS backgrounds need alt text?
No. A background-image does not have an alt attribute. For important content, use <img> with alt text. Decorative backgrounds do not require an alternative.
Does AI-generated alt text affect rankings in Google Images?
Quality alt text is one of the signals used by Google Images. AI helps create meaningful descriptions faster. The content and relevance matter more than how the description was generated. Check that the result matches the image content.
How do I process large image catalogs?
Upload images to an AI tool in batches, generate alt text, and export the results. Integrate with your CMS through an API if available. Set aside time for spot checks, especially for main pages and top products.
Common mistakes when generating alt text with AI
| Mistake | Solution |
|---|---|
| Overly generic wording (“product image”) | Add specifics: brand, model, color |
| Keyword stuffing | Keep 1–2 natural occurrences |
| The same alt text for similar images | Distinguish them by details: shooting angle, background, accessories |
| Ignoring page context | Take the page topic into account when generating alt text |
| Descriptions that are too long | Shorten to 125 characters and keep the essentials |
Conclusion
AI-generated alt text is a practical way to automate image SEO without sacrificing quality. Vision models analyze image content and create meaningful descriptions in seconds. Key rules: keep alt text under 125 characters, describe the content, include keywords naturally, and use unique alt text for each image. Editorial review remains an important step, especially in specialized niches. Use the reChecker AI Alt Text Generator to process catalogs and galleries in batches—this can save hours of manual work while maintaining SEO impact and accessibility. Start with a pilot batch of 50–100 images, assess the quality, and adjust the prompts if necessary; then scale up to the full catalog. The results pay off even with hundreds of images: manual work takes 2–3 minutes per image, while AI takes seconds.