Image SEO starts with discoverable image URLs and a useful page explaining what the image shows. Write alternative text for the image purpose, use descriptive filenames and keep the picture clear enough to be useful. These practices support accessibility and search understanding; they do not guarantee indexing or a particular ranking.
Make the image discoverable
Google documents finding images in the src attribute of HTML img elements, including those inside picture elements. It does not index CSS background images in the same way. Keep a fallback src when using responsive markup and ensure important image resources are accessible to crawlers. An image sitemap can aid discovery, but it is not a guarantee of inclusion.
Describe the meaning, not a list of keywords
Write alternative text that serves as a useful replacement in the page context. A decorative image can have an empty alternative rather than repeating nearby text. Captions can explain visible content or attribution without forcing every detail into alt text. Avoid stuffing the same product terms into every field.
Illustrative example: for a product detail showing stitching, describe that visible detail rather than repeating only the store name and a generic purchase phrase. Keep the description consistent with the actual photograph.
Use filenames and page context together
Google says filenames provide light clues about the subject. A short descriptive name can be helpful, but the surrounding page title, text and image relevance also matter. Renaming a file does not replace a useful landing page, and changing already-used URLs without maintaining references can create broken images.
Check quality and delivery
Use clear images and appropriate responsive dimensions. Compression can help delivery when downloads are a bottleneck, but excessive artifacts undermine usefulness. Inspect the rendered page, verify resource URLs and review search reporting over time if you have access. Do not promise ranking improvements from a fixed quality number, a new format or simply removing metadata.