Fix not actually setting the compression level

How I managed to leave this line of code out is a mystery. Sigh. Too bad I didn't notice yesterday. It could have been in the slipstream release you made. Sigh again.

Second commit: ensure that icons are scaled to a 128x128 box when they are composed. Handles the case where the original icon was smaller than that, and also handles the case where the user snuck a large image into the icons folder.