Context: https://help.imgur.com/hc/en-us/articles/41592665292443-Imgur-access-in-the-United-Kingdom
To qualify, Imgur must be accessible to UK users for a period of at least 7 days from market creation to the end of 2025.
If the site is generally accessible (main page and posts/images) but some posts are inaccessible without age verification (e.g. NSFW posts) then that will qualify as accessible.
If the site requires logging in, that will NOT qualify as accessible.
If the whole site requires any inconvenient form of age verification (e.g. face-scanning, ID verification, bank card verification), that will NOT qualify as accessible.
If Imgur removes its geo-blocking, but a major UK ISP institutes its own blocks of the site (or any other major blocking mechanism from a UK entity is instituted), that will NOT qualify as accessible.
If Imgur institutes any sort of partial general blocking e.g. a quota system, that will NOT qualify as accessible.