This has been doing the same thing to me for over a week now. At first I thought it was the new photobucket as I've been having issues with them as well, now all of a sudden I realize it's been Paint.Net the entire thing as I tried to upload it to another server and it looked the same way. I run a website and use .PNG images for all my text so I can use them without backgrounds... Any ideas?
Example of .PNG images made two weeks ago: http://i618.photobucket.com/albums/tt270/Bella222009/Posting%20Templates/bentemp_zps14c0bc84.png
Example of .PNG image made today: http://i618.photobucket.com/albums/tt270/Bella222009/Posting%20Templates/hybrids.png
Notice the one today how there looks to be white grains around the words?
Example of .JPG Image made today: http://i618.photobucket.com/albums/tt270/Bella222009/Posting%20Templates/Temp1-1.jpg
Example of .PNG Image made today: http://i618.photobucket.com/albums/tt270/Bella222009/Posting%20Templates/Temp1.png
See the grainy quality of the .PNG image? Any ideas on how to fix this?