When you're making your forum signature in Paint, Preview, Photoshop or whatever - I strongly suggest to save it as a GIF rather than a JPEG. Why? The JPEG format compresses and decreases the quality of the picture, making it look lower-quality. GIF keeps the picture's quality looking healthier and more professional. Preview (and some other programs) allow you to change the quality level changing the file size, but just to be sure, go with GIF.
Also never upload a picture that is smaller or bigger than the size it is allowed to be.
Change that yourself or the picture will look again compressed or stretched making pixels appear and changing the image's quality.
I am going to add a picture of a Comparison bellow just so that you guys know what I'm talking about.
P.S. If you plan on making a forum signature with a "Blank" background, it is impossible. For an image to be saved with a blank background it must be in .TGA format! So instead what you do, is take someone else's signature as a starting point (like mine) because it already has the background color of the forum post on Newgrounds. Then use that color to make it look as though you have blank sections or just a blank background to your forum signature.
