06-26-2016, 03:17 AM
(06-25-2016, 11:12 PM)Mancom37 Wrote: I am using apint.netI think you means paint.net.

As oort said, you just need to export or save as the image using one format that supports transparence.
Check this short video tutorial about that. It's exactly the same process I used in Gimp to make transparent the black area in your image.