2GB is gigantic. It shouldn't come anywhere near that unless you have looked at 40,000 image pages in the last couple days, or next f apple is strangely deciding to count normal browser caching as imgflip storage.
We did push a change to use less caching in the home screen app though, so if you close your browser and Imgflip and restart, then it should start handling storage more efficiently. With the change, you could view millions of images and storage should be capped around 5MB