It would still make it noticable. The best thing to do would be fading both edges. Make them overlap, and fade the edges with a soft eraser, then put a solid black layer behind the images to make sure it stays solid and doesn't have any transparency((which could possibly screw up depending on how you save the picture)).
Avatar: 1/5 It's an image, with some text.
Sig: 2/5 A little better, but still not much.
Thats what I ment, just in more detail