The site icon is the small square image WordPress uses for your favicon, your browser-tab icon, the bookmark icon, and the icon a visitor gets when they add your site to a phone home screen.
It is a core WordPress feature, not a theme one, so it works the same in every theme and survives a theme change.
Setting it
Appearance → Customize → Site Identity → Site Icon → Select site icon.
WordPress asks for an image at least 512 × 512 pixels and square. Upload something larger and it will offer a crop; take it, because the icon is used at sizes from 16px up and a lopsided crop shows.
What makes a good one
At 16 pixels there is room for one shape or one letter, and nothing else. A full logo shrunk to a favicon is a grey smudge.
- One glyph, one monogram, or one simple mark.
- High contrast against both a white and a dark browser chrome — tab bars differ, and dark mode is common.
- No thin strokes. They vanish.
- PNG with a solid background is safer than transparency: some contexts composite a transparent icon onto an unpredictable colour.
Check it at the real size before you commit — zoom your browser out, or just look at the tab.
Where it shows up
| Context | Size WordPress generates |
|---|---|
| Browser tab, bookmarks | 32 × 32 |
| iOS home screen | 180 × 180 |
| Windows tile | 270 × 270 |
| App icon / manifest | 192 × 192 |
WordPress produces all of these from the one upload and emits the right tags in <head>. You do not need a favicon plugin.
If it does not change
Browsers cache favicons aggressively — more aggressively than almost anything else. After changing it:
- Hard-reload the page (Ctrl/Cmd + Shift + R).
- If it persists, open the icon URL directly and reload that, or try a private window.
- Behind a CDN or a caching plugin, purge the cache.
The icon is nearly always right on the server before it looks right in your tab.