Product images help customers decide what to buy. They show details that product descriptions can’t fully communicate, from fabric texture and color to size, finish, and fit. But large image files can slow down product pages, while missing or poorly written alt text can make images less useful to people using screen readers.
Image SEO helps you address both problems. The goal is to make images accessible, keep pages fast, and give search engines useful information about the products you’re selling.
For an online store, start with three things: write descriptive alt text, compress images without noticeably reducing quality, and choose image formats that suit the content. Then make sure your store displays appropriately sized images on desktop and mobile.
1. Write Alt Text That Describes the Product
Alt text is a written description of an image added through its HTML alt attribute. Screen readers can announce it to users who can’t see the image, and search engines can use it as additional context for understanding the image.
The best alt text describes what’s actually visible and includes relevant product details when they help identify the item. It shouldn’t read like a list of search keywords.
Consider a store selling leather jackets. These examples show the difference.
| Image | Weak alt text | Better alt text |
|---|---|---|
| Black leather jacket on a model | jacket | Black leather biker jacket with silver zippers worn by a model |
| Close-up of jacket stitching | leather jacket mens jacket leather clothing | Close-up of black leather jacket stitching on the shoulder |
| Brown leather wallet | wallet | Brown leather bifold wallet with six card slots |
| White ceramic coffee mug | best coffee mug buy online | White ceramic coffee mug with a curved handle |
The stronger examples identify the subject and describe useful visible details. They give readers meaningful information without forcing keywords into every phrase.
How to write better product image alt text
Follow these practical steps:
- Describe the main subject. Name the product or the part of the product shown.
- Include distinguishing details. Mention color, material, shape, pattern, or features when they’re visible and relevant.
- Use natural language. Write a short description a person could understand without seeing the image.
- Keep each description specific to its image. A front view, back view, and close-up may need different alt text.
- Leave out promotional language. Words such as “best,” “premium,” and “must-have” usually don’t describe the image.
You don’t need to include every product attribute. If a photograph shows a blue cotton shirt, mentioning the shirt’s color and material may be enough. There’s no need to add its price, shipping policy, or unrelated product specifications.
Should you include keywords in alt text?
Include a target keyword when it accurately describes the image and fits naturally. Don’t repeat the same phrase across every product image simply because you want the page to rank for it.
For example, black leather biker jacket with quilted shoulders is useful when those details appear in the photograph. Adding several variations of “buy black leather jacket online” doesn’t improve the description.
Also, don’t confuse image alt text with image captions or surrounding product copy. Each serves a different purpose. Alt text describes the image for users who can’t see it, while captions can provide additional information to all visitors.
When should alt text be empty?
Not every image needs a written description.
If an image is purely decorative, such as a background flourish or a visual separator, use an empty alt attribute (alt=””). This helps prevent screen readers from announcing unnecessary details.
For a linked product image, the alternative text should communicate the link’s purpose or identify the product. If an image contains text that conveys essential information, provide that information in an accessible form rather than leaving it available only in the image.
For product galleries, review the output of your ecommerce theme to confirm that meaningful images have appropriate alt attributes. Don’t assume every image is handled correctly just because the store platform supports alt text.
2. Compress Images Without Losing Important Detail
Image compression reduces the amount of data a browser needs to download. For an online store, that can make product pages load faster, particularly when customers browse large product galleries on mobile connections.
The challenge is preserving enough detail for shoppers to judge the product. A compressed leather jacket photo should still show the grain, stitching, and finish. A product image that looks blurry or washed out can undermine customer confidence.
How to compress ecommerce images
Use this workflow when preparing product photos for your store.
Step 1: Resize the original image.
Don’t upload a huge photograph if your website only displays it at a much smaller size. Check the actual dimensions used by your product gallery, collection cards, and zoom feature.
Keep a high-resolution original for future use, then create appropriately sized versions for the website. The right dimensions depend on your theme, layout, and whether customers can zoom in.
Step 2: Choose suitable compression settings.
Lossy compression removes some image data to reduce file size. Lossless compression preserves the original image information but may produce larger files.
For product photography, start with a reasonable lossy compression setting and inspect the result. Look closely at textures, fine edges, gradients, and small product details. If the image looks noticeably worse, adjust the settings.
Step 3: Compare file size and visual quality.
Check the original and optimized versions at the size customers will actually see. Don’t judge quality only by zooming far beyond the intended display size.
For example, a 3 MB product photograph might be reduced substantially without an obvious visual difference. The actual reduction depends on the image, dimensions, format, and compression settings, so test your own files rather than assuming a fixed saving.
Step 4: Automate image optimization where practical.
Stores with hundreds or thousands of product images can benefit from automated compression during upload or through an image delivery service. Review the output before applying the same settings across the entire catalog, especially if your products rely on fine visual details.
Don’t forget mobile performance
A product image that looks sharp on a desktop monitor may be unnecessarily large for a phone screen.
Use responsive images so the browser can select a suitable image size for the visitor’s device and layout. HTML’s srcset and sizes attributes support this approach, while the picture element can offer alternative formats. Your implementation should retain a valid fallback image. Google’s image SEO guidance explains how these techniques help websites serve images appropriately.
For a practical performance review, run important product and collection pages through PageSpeed Insights. Pay particular attention to the largest visible image, image delivery, and recommendations related to loading performance.
If the store also needs broader technical improvements, our SEO services can be a relevant starting point for reviewing site structure and organic search performance.
3. Choose the Right Image Format
Image format affects file size, visual quality, transparency, and browser compatibility. You don’t need to use one format for every image on your store.
These are the main options worth considering.
| Format | Best use | What to know |
|---|---|---|
| WebP | Product photos, lifestyle images, and many general website images | Supports lossy and lossless compression, including transparency. |
| AVIF | Product photography and other images where smaller files are a priority | Can provide excellent compression, but test image quality and delivery compatibility. |
| JPEG | Photographs and existing product image libraries | Widely supported and useful for photographic content, but may produce larger files than newer formats. |
| PNG | Images that need lossless quality or transparency | Useful for certain graphics, although it can be unnecessarily large for photographs. |
| SVG | Logos, icons, and simple vector illustrations | Scales cleanly without the pixelation associated with raster images. |
WebP is a practical default for many ecommerce images. AVIF is also worth testing if your image pipeline supports it. Both can reduce file sizes compared with older formats, although the result varies by image and settings.
WebP vs. AVIF: Which should your store use?
For many stores, WebP offers a straightforward balance between compression and browser support. AVIF can deliver smaller files in suitable cases, making it worth testing on image-heavy pages.
Compare both formats using representative product images. Check file size, color accuracy, sharpness, and how the images appear across your supported browsers.
You don’t need to convert everything to AVIF simply because it’s newer. If the improvement is negligible or your delivery setup becomes unnecessarily complicated, WebP may be the more practical choice.
When should you keep PNG or JPEG?
Keep JPEG when it already provides acceptable quality and your current setup serves it efficiently. Converting an entire library isn’t automatically worthwhile if the savings are small.
PNG remains useful for graphics that need transparency or precise reproduction. However, for a standard photograph of a handbag, chair, or pair of shoes, a well-compressed WebP or AVIF file may be more efficient.
If you serve modern formats, configure the delivery system to provide an appropriate fallback where needed. The browser should receive a format it supports, without broken product images becoming a new problem.
4. Optimize Image Filenames and Context
Alt text and compression aren’t the only considerations. Search engines also use information around an image to understand its subject.
Give important images descriptive filenames before uploading them. For example:
- IMG_2048.jpg becomes black-leather-biker-jacket.jpg
- product-final-2.png becomes brown-leather-bifold-wallet.png
- photo1.jpg becomes white-ceramic-coffee-mug.jpg
Keep filenames concise and accurate. There’s no need to squeeze several keyword variations into them.
Place images near relevant product descriptions and headings. A photograph of a black leather jacket belongs on a page that explains that jacket, not in an unrelated section where its purpose is unclear.
Also check that important images are embedded in a way search engines can discover. Standard HTML image elements are a reliable choice. Review lazy-loading behavior to ensure it doesn’t prevent important images from appearing promptly. Google’s image SEO best practices cover image discovery, filenames, responsive images, and page context.
5. Build an Image SEO Checklist for Your Store
Image optimization works best as a repeatable process rather than a one-time cleanup.
Use this checklist when publishing new products or auditing existing pages.
- Write descriptive alt text for informative product images.
- Use empty alt attributes for purely decorative images.
- Give different product views descriptions that reflect what each image shows.
- Remove unnecessary image dimensions while preserving the quality customers need.
- Compress photographs and compare the results visually.
- Choose WebP, AVIF, JPEG, PNG, or SVG according to the image’s purpose.
- Use concise, descriptive filenames.
- Check that product images display correctly on mobile and desktop.
- Test key product and collection pages with PageSpeed Insights.
- Verify that image galleries, zoom features, and responsive image delivery still work after changes.
Start with pages that matter most to the business. Your best-selling products, high-traffic collections, and landing pages are sensible priorities. Fix obvious problems there before spending hours optimizing images on rarely visited pages.
If your store has a large catalog, make these checks part of the product publishing workflow. A consistent process makes it easier to maintain image quality as new products arrive.
Make Image SEO Part of Your Store’s Routine
Image SEO isn’t about adding keywords to every photograph or chasing the smallest possible file size. It’s about helping customers understand products, making images accessible, and delivering visual content without unnecessary delays.
Start by reviewing a handful of important product pages. Improve their alt text, compress the largest images, test modern formats, and check how everything loads on mobile. Once you’ve identified what works, apply the same standards across the rest of your catalog.
If you’d like help identifying image-related issues alongside broader technical SEO and website performance problems, you can contact Nova X Ventures to discuss your store and decide which improvements make the most sense.