Of course with a new avatar comes a new avatar help subject, this time my avatar is not appearing transparent in the background like it should, i am using paint.NET and using the eraser tool i completely cut out the Yin Yang. I then proceeded to save and upload it (JPEG) and the clear part kept appearing white. i used 2 other file types (PNG and GIF) but the background keeps appearing visible, any ideas?
EXTRA INFO: The last avatar i used,

(because i got banned) as you can see is perfectly transparent. I also made this in paint.NET. and uploaded it as a PNG