Google Images is a substantial traffic source for retail, recipes, design and travel. Images are indexed based on the image itself and on the page that hosts it.
What helps
- Descriptive filenames,
navy-linen-shirt.jpg, notIMG_4821.jpg. - Meaningful
alttext that describes the image, not a keyword list. Decorative images takealt="". - Relevant surrounding text, captions and nearby copy give context.
- Standard
<img>elements. CSS background images are not indexed as images. - Explicit
widthandheightto prevent layout shift. - An image sitemap when images are on a CDN or loaded by script.
What hurts
Blocked image directories in robots.txt, images that only load on interaction, and enormous files that time out.
Alien Road recommends: write alt text as if describing the image to someone on the phone. That produces text that serves screen-reader users and Google equally, and it naturally avoids the keyword stuffing that makes alt attributes useless for both.