Sorry if this is obvious, but I reuploaded a tileset today and wanted to change the screenshots so they match. However, I can't find any function to do this. Do I need to ask an administrator, or am I blind/stupid and can't find the button?

They say that there is a feature to do this, but I am neither able to do it.

Apparently this feature was, by error, only available for site administrators. I've fixed the problem and you should now be able to delete screenshots from your own uploads.

Great, thanks!