There are a lot of great skins to download. Call me fussy, but there always seems to be one or two small things I'd like to change on an otherwise great skin.

My question is technical and ethical. First, is it considered ethically acceptable to download a skinner's theme and modify it slightly for one's personal use?

Second, is it even possible to do this? I installed the free version of SkinStudio to see if I could make a few minor changes on a downloaded theme. The theme was "Copyrighted" and nothing seemed to work on that theme. Admittedly "nothing working" could be me not knowing what I'm doing

If it's possible and acceptable to "tweak" some of the great skins that are copyrighted, I might purchase SkinStudio and make an effort to learn more. I don't have a lot of interest in making skins from scratch, but I do have a keen interest in making small modications in color and functionality on some of the downloaded skins in order to better suit my tastes. Is it okay and possible to do this?

Thanks.