HOW TO MAKE ROUNDED ICONS

Try setting the corner radius

In this application I found it easier to use the square tool, then go to the far right corner and select the outline tool in the southeast corner, then I would click outside the picture and drag the oval shaped outline to the corners, then select the flood fill eraser and fill every corner manually [this only works easily when the picture isn't too busy on the corners and the outlines created by the square tool allow the corners to be filled selectively] if the flood fill tool does not cover each corner, I then use the pencil eraser tool to finish filling in the corners. Then save as and export.