I've implemented a new file format into ascii-paint, the Ascii Paint Format, which uses an .apf extension. This format is more flexible than the .asc format. As well as storing the image, it can store program settings (like grid width), and will be able to handle future additions to ascii-paint, like layers. (It also conforms to the RIFF standard.)
But it needs
testing! If you want to help, please download the latest 0.3.3 release, from here (
https://bitbucket.org/bpio/ascii-paint/downloads/ascii-paint-bpio-0.3.3-beta.zip). Then try and load "animtest.apf", does it work? Good! Now try to make an image, with custom grid settings (visible,width,height), save it with an ".apf" extension, then change all the settings and image, reload the file, and hopefully your old grid settings (and image) should load. Thanks!

Oh, and while you're at it, you can test fullscreen mode. (ALT+ENTER)