I was recently trying a USB thermal printer, and I wanted to test the improved image handling in python-escpos, courtesy of my friend Zouppen. First of all, do not buy this printer. The print quality is extremely shoddy; I get a rorschachuesque splotch when I try to print a solid-black block.
So anyway, I needed a vertically long image to test, and what is long? Longcat is long. I usually scoff at meme propagation, but what the hey. So, here is a longcat generator. Base image by some fine dude on an imageboard somewhere. And here's the result:
forkable on Github. Essentially, it's missing a "save stitched image file as..." button. I printed the image as PDF, then used ImageMagick to convert the file to GIF (understood by the printer).