Did you make the sprites?
Do you know what an alpha channel is?
If you made the sprites, but you don't know what an alpha is, you should probably hold off on the graphics, and do some research on the mechanics.
If you didn't make the sprites, but you know what transparencies are you should probably look for a better rip, or use some place holder. Nobody cares what a dev looks like graphics wise.
No to both?
..... eeeek.