Nice dragon. An alpha channel is a mask, which tells the program displaying the image what is transparent. How that is displayed depends on the program. Some use the conventional checker pattern, some use plain white (web browsers) and it looks like your program ignores it completely.
Something for you to try, use the eraser tool in anti-erase mode. That uncovers the "hidden" background which in your case is black. If you make an image in Gimp then when exported as a png the current background colour (often white but can be anything) is used.
Which program are you using ? Are there any special requirements for images with transparent backgrounds ? Sometimes a property known as a clipping path is used but that is more associated with PhotoShop.
Something for you to try, use the eraser tool in anti-erase mode. That uncovers the "hidden" background which in your case is black. If you make an image in Gimp then when exported as a png the current background colour (often white but can be anything) is used.
Which program are you using ? Are there any special requirements for images with transparent backgrounds ? Sometimes a property known as a clipping path is used but that is more associated with PhotoShop.