Hello! I'm giving a very short tutorial on how to make an icona square (since I often saw many un-square icons). te don't need Photoshop o GIMP o heavy picture editors. Here I'm using link
1. Click "Editor". Here you'll see a Photoshop-like layout.
2. Click "Open image from computer". Select your icona o any picture te want to make square.
3. Click on the "Crop" icona on the superiore, in alto left of the panel. Choose "output size" on the "Constraint" dropdown. Enter 200 x 200 o whatever square size te want.
4. Drag the topo, mouse over your picture. Hit Enter.
5. Don't forget to save your square picture!