Hover-zoom troubleshooting
Hover-zoom extensions break for a small number of well-understood reasons. This page helps you work out which one you have hit, because the fix is completely different depending on the answer — and in one of the three cases there is no fix at all.
Diagnose it in thirty seconds
- Does it fail everywhere, or only on some sites? Open two very different sites — a Google Images results page and a Reddit thread, say. If one works and the other does not, the extension is running fine and its rule for the broken site is out of date. Skip to Cause 2.
- Is the extension still enabled? Check your extensions page. A browser update can disable an extension that no longer meets store policy, and it does so quietly. If it shows as disabled or says it was removed, you are in Cause 1 or Cause 3.
- When did it last get an update? Look at the store listing’s last-updated date. An extension with no release in two or more years will not be fixed for either of the first two causes. That is Cause 3.
Cause 1: Manifest V3
Chrome retired Manifest V2, and extensions that were not migrated stopped running. Hover-zoom tools were hit unusually hard because the old architecture let them do things — background pages that stayed resident, remotely-fetched rule updates, broad host access — that Manifest V3 restricts. Several were abandoned rather than rewritten. The engineering write-up covers what specifically broke.
Fix: none, from your side. Either the developer ships a V3 version or the extension is finished. Firefox still runs some V2 extensions, which is why a tool that died on Chrome may keep working on Firefox for a while.
Cause 2: the site changed
Hover-zoom works by recognising a site’s image URLs and page structure, then deriving the full-resolution URL from the thumbnail. When a site redesigns its markup or changes its image CDN, that derivation stops working until someone updates the rule. This is why previews fail on one site while everything else is fine.
Fix: update the extension, then update its rules if it keeps them separately — Imagus calls these sieve rules. If the extension is actively maintained, reporting the broken site usually gets it fixed in the next release.
Cause 3: the extension is no longer maintained
This is the common case, and the frustrating one, because it presents exactly like the first two. The category has a long history of popular extensions being abandoned, sold, or — in the case of the original Hover Zoom — caught collecting and selling browsing data and never recovering trust. An unmaintained extension accumulates broken sites permanently.
Fix: migrate. Check the last-updated date on the store listing before you invest more time in debugging.
Extension-specific guides
- Imagus not working — Previews stopped appearing, or only work on some sites. What breaks, what to check, and how to move your sieve rules.
- Hover Zoom not working — Hover Zoom and Hover Zoom Plus stopped previewing images. The causes, the fixes, and the privacy history worth knowing first.
Looking to compare maintained options rather than fix a broken one? The Hover Zoom alternatives roundup and Imagus alternatives roundup cover every option still shipping, including the ones that are not us.
If you are troubleshooting Ultra Zoom
Ultra Zoom’s own troubleshooting lives on the Help page, and the FAQ covers the common “it shows a crop instead of the whole image” and “a site I use is not supported” questions. If neither helps, send us the URL — a broken site usually becomes a rule update within a week.