Stitch'n'Glitch is an application to aid the experimentation of mixing image corruption with traditional cross stitch techniques. Images can be uploaded to the application, colours can be reduced (through dithering or otherwise) before or after glitching. Export options include pdf vector image, CSV file of hexadecimal values or pdf cross stitch pattern, of course.
The project has its own mini-site at stitch-n-glitch.com where there is much more information, images, downloads and links.
Version 1 (2012) can still be downloaded from here The second version (2013) of the software added the ability to glitch and dither even large images, export patterns as multi-page PDFs with simplified colour symbols, more dithering algorithms and improved User Interaction. It can be downloaded here. Code for all versions is hosted on my own github.
Image corruption code adapted from the corrupt project by Recyclism.