I think this is a bug. I always put numbers when deliver the order but Fiverr for unknown reason has its own numeration order. It creates confusion because clients refer to what they see in the thumbnail view and I always think that they are referring to my numeration.
Couldn’t use use letters in your own description (A-E instead of 1-5) to make it easier? I don’t know if it’s a bug, but it may not be something they can change fast.
Of course I could and I will, probably because it’s confusing. But you know, normally in every file system (like in Windows or Mac) if you sort by name while put the number on the end of the name file it will treat them properly. I know they won’t fix it, just want to mention.