I've been trying to upload a skin I made on Skindex, to Minecraft, the skin downloads as a 64x64 .PNG automatically so I can't change the size from what I understand. However trying to upload it gets me the error message that I need to use a 64x64 or other sizes PNG to upload as a skin. 

I've had somebody else try to download and upload it and it works for them, so it shouldn't be a problem with the skin itself, however I am playing Mobile and they uploaded on the computer so it could be a glitch. If you have any info about this I'd love to hear back and see if it can be fixed. 

For ref. This is the link to my upload. https://www.minecraftskins.com/skin/22869234/selene/

And these are my downloads.