Confusing "Upload failed" message

[Supershroom]

I've got these messages various times when I added screenshots: after clicking "Submit changes", there was a sudden pop-up message saying "Upload failed!" and when clicking OK, I returned back to the Edit screen. But then I noticed that my changes have still gone into effect.

So, whenever you see this, just click OK and return to the Edit screen, and then go back to the forums / portal hub / whatever, the changes should still be successful.

[Triple J]

I've been experiencing this too. It might have something to do with the file size of your level code, but what do I know.