Image Alt Text and Image SEO

Images are often the most persuasive part of a web page: product photos, project galleries, team portraits, infographics, diagrams and screenshots. They are also usually the heaviest part, frequently accounting for most of a page’s file size. Unoptimised images slow pages down, especially on mobile networks, which frustrates visitors and affects how search engines evaluate page experience.

Search engines cannot see images the way people do. They rely on surrounding text, file names, alt attributes, captions and structured data to understand what an image shows. Visitors who use screen readers depend on alt text to know what an image conveys. When images lack descriptions, use meaningless file names like a camera’s default numbering, or are inserted as decorative backgrounds containing important text, both accessibility and search visibility suffer.

ViV Softech Solution is a website designing and digital marketing agency based in Delhi. We optimise images for websites and online stores across India. This page covers writing useful alt text, file names and captions, performance optimisation including compression, formats and responsive images, image search visibility, accessibility considerations, bulk optimisation for large libraries and what affects cost. Image optimisation improves accessibility and speed reliably; its effect on rankings and image search traffic varies by site and topic.

Alt text, the alternative text attribute on an image, is read aloud by screen readers and displayed if an image fails to load. It also helps search engines understand images. Good alt text is about describing the image’s content and purpose, not about inserting keywords.

Describe what matters

Focus on what the image shows that is relevant to the page. A product photo might be described by product name, colour and key feature; a project photo by what was built and where; a team photo by who is pictured and their role.

Keep it concise

A short phrase or sentence is usually enough. Long paragraphs belong in captions or surrounding text.

Consider function

If an image is a link or button, the alt text should describe where it goes or what it does, such as download brochure, rather than what it looks like.

Leave decorative images empty

Purely decorative images, such as background patterns or dividers, should have empty alt text so screen readers skip them.

Text in images

If an image contains important text, such as an infographic or banner offer, that information should also be available as real text on the page or in the alt text.

Avoid keyword stuffing

Repeating keywords in alt text does not help users and can look manipulative. Natural descriptions often include relevant terms anyway.

• Right dimensions: upload images at sizes close to how they are displayed instead of huge originals scaled down in the browser.
• Compression: reduce file size with quality settings that preserve visual appearance.
• Modern formats: serve formats such as WebP or AVIF to browsers that support them, which are often much smaller than traditional formats at similar quality.
• Responsive images: provide several sizes so phones download smaller files than large desktop screens.
• Lazy loading: delay loading images below the visible area until the visitor scrolls, while making sure the main hero image loads promptly.
• Reserved space: specify image dimensions so layouts do not jump as images load, improving visual stability.
• Content delivery networks: deliver images from servers closer to visitors where appropriate.
• Avoid oversized sliders: large auto-playing image sliders often slow pages more than they help.

Image work is closely related to our website speed optimization service.

Image optimisation is not only about search. Many visitors rely on assistive technology, have slow connections or have images turned off. Accessible images benefit all of them. We check that meaningful images have appropriate alt text, decorative images are hidden from screen readers, important information is not available only inside images, charts and infographics have text explanations, and image links describe their destination. These practices align with widely used accessibility guidelines and make your website more inclusive.

1. Audit: image sizes, formats, alt text coverage, file names and loading behaviour. 2. Prioritise: key pages, products and galleries. 3. Performance setup: compression, modern formats, responsive images and lazy loading. 4. Alt text and context: write or improve alt text, captions and nearby text for priority images. 5. Technical checks: structured data, sitemaps and crawlability. 6. Guidelines: image upload and alt text rules for your team. 7. Verify: speed tests and accessibility spot checks.