After T250144 is done, the getting of real thumbnail should be implemented.
The most appropriate is PageImages but might other options are possible. So it should be defined later.
- Hook 'SearchResultProvideThumbnails' introduced in T250144, should be implemented
- The hook should return thumbnails for a given list of pages (or null if no thumb for the page)
- Tests should cover changes properly
- Thumbnail should be 200x200 px (changed from 512x512)
- Thumbnail's size should be optional.