andrewfinlayson said in his own words "Cross posting between Reddit and Imgflip where the image is displayed on both sites is allowed.
If the image creator only has an account on Reddit and cross posts on both sites, you will see "Made by a Redditor" on the image page here and their Reddit username will be displayed on the corresponding Reddit post. If the image creator has accounts on both sites and cross posts, the Imgflip username will be displayed on the image page here and the Reddit username will be on the post there.
When scrolling through "New" in the fun stream, you may occasionally notice a meme with lots of views, like hundreds or even thousands of views. Sometimes those are creations that are cross posted here and on Reddit. When you click on the image in "New" and go to the image page where you can comment, that's where the username may change from anonymous to "Made by a Redditor"."