Two names for the same thing
Search engines and screen readers share a common problem: they can't see images. Google increasingly processes image content, but at heart both rely on a text description to understand what an image shows. From this follows a surprisingly freeing insight: the measures for image SEO and for accessibility are largely the same. You don't optimize twice, but once — properly.
Alt text: the shared heart of it
The alt text is the best example. A screen reader reads it to blind users; a search engine uses it to understand the image content and place it in image search. The clever part: alt text that informs a person well also informs the search engine well.“Red women's running shoe, side view” helps the blind user and ranks for “red running shoe.” You don't write an SEO version and an accessibility version — you write an honest description, and it serves both.
Why keyword stuffing loses on both sides
The classic SEO mistake shows especially nicely that both goals coincide. An alt text like “compress image free JPG PNG WebP online tool shrink image” is
- for screen-reader users meaningless word-jingle that describes nothing;
- for modern search engines a recognizable manipulation signal that harms more than it helps.
What annoys the one, the other penalizes. Honest description wins on both sides.
The other shared factors
| Measure | Accessibility benefit | SEO benefit |
|---|---|---|
| Descriptive alt text | screen-reader access | image-search ranking |
| Descriptive file name | fallback info | context signal |
| Caption / context | understanding | topical placement |
| Real text instead of text in image | readable, zoomable | indexable |
| Fast loading | better experience | ranking factor |
Every row serves both columns. Optimize one and you get the other for free. The technical factors like load time are covered in detail in Image SEO.
The one exception
There's exactly one point where they diverge: decorative images. For accessibility they get an empty alt text (alt="") so screen readers skip them — for SEO they're simply irrelevant. No conflict, just a shared non-responsibility. Details in Decorative images and empty alt text.
The mindset
So the best advice is also the simplest: optimize for humans. Whoever prepares images to be usable for all people — with clear descriptions, real text, good contrast, fast loading — has automatically optimized for search engines too. Accessibility isn't an SEO opponent, but the most honest route to good SEO.
In short
- Same measures serve screen readers and search engines.
- Honest alt text beats keyword stuffing on both sides.
- Real text, good context, fast loading help everyone.
- Optimize for humans and SEO follows.