I was talking to a friend who kept submitting their head to fix issues and it made me point out how bad I feel when I have to submit an upload 10+ times. Whenever I uplaod something I always spot a bunch of things I don't pick up on like random pixels i forgot to remove or one frame being different than the others by a little bit. Then I thought to myself and wondered if having a way to open your stuff locally was possible, so only you can see it ingame just to see if it all looks well.
So you could designate a head/body on like the first page of each type and give players the ability to upload their files similar to a Minecraft resourcepack. This would cost nothing obviously and it'd allow people to make corrections on their uploads based on their favourite bodies/hats/ without having to flood the upload queue.
I'm creating this post at a bad time because it's late and i'm exhausted so I hope I'm wording it well enough for people to understand.