The touchscreen paint program has been upgraded in the first post. It is now at version 1.3.
Check out the script code in the first post. It is getting smaller, and simpler, and better. It will be of more general use when it evolves into an onscreen touchscreen keyboard than can be called from shell scripts.
As the versions progress, the code is following a typical pattern for me, where I add features by removing limitations, which has the side-effect of making the code smaller and simpler. As of version 1.3, the artwork you create with this program is automatically saved to touchpaint.raw on your USB drive when you exit the program (the previous image is renamed to touchpaint.raw.bak).