@Mairo: Hi! I flagged my own post for deleting because I had uploaded the wrong file (lower quality .JPG instead of .PNG). Though now when I try to upload my picture again (.PNG), it say the post already exist... What do I do? I can't upload this pic. :(

@Akacia: reminder that by default, e621 will show you 900px JPG sample of the upload, you have to click "full size" to see full image, you can check metadata on left side panel and you can change default display from user settings.

By the way, my post DID get deleted (by you). So I don't get it.

@Akacia: It gives that error message only if you are uploading identical image. Either you uploaded the correct png version in the first place, or you are trying to upload same jpg version.

@Akacia: If it says it already exists and takes you to the deleted image then the MD5 matches....which means you tried uploading the exact same file that you had deleted because it was the wrong file.

@Akacia: Or you have the 1 in 340282366920938463463374607431768211456 chance that the MD5 is the same for both different files.