Minecraft skin not showing up in game

One day I decided to tweak the colors of my Minecraft skin. I then selected the skin in the launcher and it worked. A few days later, NONE OF THE AVAILABLE SKINS WORKED, neither the "Steve" skin. I had the Alex skin only and I am very upset.

I will provide my current skin and please check if there's something wrong with the image (although the image is 64x64 in the .png format).

I edited the skin with paint.net

(I did not know which version I shall insert, but it works in any version above 1.7 I think)