My daughter went to an Ed Sheeran show last year and made a customized t-shirt for herself. She needed some buttons, so I suggested this shape she had printed in the t-shirt: an orange paw. We scanned her drawing, put it in vector form (Inkscape is great!) and added some discs in the back of the design. The larger disc is there to hold things together; the second one to hold the hole for the thread.