When importing a Minecraft Skin, it says it's not a Minecraft Skin even though it is.

When you are importing a Minecraft Skin, it says "It's not a Minecraft skin, silly" even it is a Minecraft Skin. (Skin is from a website called "Skindex")

 

Expected Result:

Minecraft would accept the chosen (Minecraft) skin.

 

Actual Result:

Minecraft considers the skin NOT a Minecraft skin.