I noticed that the icons for search jump had different sizes when I loaded it in Google Chrome.
When I investigated the issue, I found the icons had 16×16, 32×32, 64×64 image sizes embedded. Chrome happened to load the larger image sizes.
The final trick was to get Chrome to reload it. I tried restarting the browser and clearing the cache. It finally worked when I uninstalled it from the extensions menu and reinstalled it from the web site.
Minimal SearchJump is available for Chrome, Firefox, and Opera.