"GIMP is not LAME: Computer geeks think they are funny, and that
how we end up with names like GIMP and LAME. GIMP is short for GNU
Image Manipulation Program. LAME is a recursive acronym for LAME
Ain't an MP3 Encoder. Together they form my mildly amusing
subheading. At any rate, whatever the shortcomings of the name,
GIMP is an excellent open source painting, drawing, and image
editing program. It is free of cost and runs on Linux, Mac, and
Windows, and supports a number of drawing tablets like Wacom.
"You'll need a batch of existing images to follow this
tutorial– photos, clipart, anything is fine. You can copy
images from Web pages by right-clicking on them, and then
left-clicking "Save as" in the right-click menu. This is legal for
private, personal use; don't commit copyright infringement by
distributing copyrighted images without permission. Visit the
Wikimedia Commons to find excellent permissively-licensed images,
and you can even share your own."