I have made tests and you are right about the error messages. They aren’t specific about the error. I will change it in the next update.
Anyway, the conditions about the file size in lower than 10mb, so it’s really strange if you were trying to upload images about 500kb. Have you checked the server conditions about this?
Before I will update the script, if you don’t want to get an error when you are adding a new item, fill al the fields please.