User blog comment:WhitePinoy/Need Help with Theme Designer/@comment-1330470-20130730051011/@comment-1330470-20130730061020

Okay. That image is a PNG. PNG images are losslessly compressed: this means that there is no reduction in quality when it is saved, and it'll look good, but in return it'll have a large filesize. I re-saved the image as a JPG, which causes a tiny loss of information (= a tiny decrease in quality) but in return reduces the filesize. Now it's less than 150 KB, and if you tile it, it should look good. http://i.imgur.com/40mUlwX.jpg I also removed the top line of pixels, as they were white, which doesn't fit the rest of the image very well, especially if you tile it.

Alternatively, you could use CSS to have the image as a background. That way, no 150KB file size limit is applied... though you should be cautious not to use a waaay too big image! (The one you linked is fine.)

BTW, these sorts of questions are better suited for the forum, for the future. =)