when you saved the logo from the official site you probably saved the file as doop jpg since that's what the site calls it the jpg extension is a good indication that the image is in the jpeg format if you don't see file extensions on your computer windows xp hides them by default you can always right click on any image on a web page and select properties or something similar there should be a field in the properties window called location or address or the like that will show you the url of the image which is as before the jpg extension is a good indicator that the image is a jpeg so that original image is already compressed as a jpeg and it will already have compression artifacts but that site doesn't seem to be an official futurama site it seems to be a fan site unrelated to fox or any of its affiliates so it's possible that there is an official fox page that will have a png version of the doop logo more likely you will find a gif version which can be losslessly converted to a png but you'll have to do some searching