Sitewide Moderators can't see image flags in all streams, only streams where they are also Stream Owners/Moderators. Image flags only appear in the
imgflip.com/approval-queue
If a valid image flag for an image page against the Terms of Use gets improperly flushed, it's virtually impossible for Sitewide Moderators to know about that, without getting a tip, or for a Global Moderator to get a
imgflip.com/request_removal
For valid image flags that get improperly ignored by a Moderator, there isn't a great way to review those actions, unless you go through every approval made by that Moderator.
If a Moderator is improperly ignoring valid 𝘤𝘰𝘮𝘮𝘦𝘯𝘵 flags, the review process can be a little more transparent using:
(copy and paste into your browser)
imgflip.com/moderations?stream=&user=&type=com_flag_ignore
I'll bet you a million kuna that Global Moderators have checked my moderation history at one point or another.