Images on my myspace appear pixelated...?

[North Ave]

When I create graphics in photoshop to use on my myspace they always appear fine on my computer (macbook pro) but when viewed on other peoples computers the images are very pixelated. So I am wondering I am doing something wrong when I create the image, or is it the image hosting site, the browser or something entirely different?-Thanks for the help.

[kut3i3 wit a booty]

dat 66.90.76.66 do not work get another plz upgrade naw im playin but that one dont work