A read[] hint for loading colored dithered images is certainly possible, and is on my roadmap for some unspecified point in the future.
Currently, images are not "transportable" resources like sounds, fonts, patterns, and modules, but I'm very close to releasing a new feature that may handle the use cases you have in mind for that sort of functionality; stay tuned.
The read[] function in native-Decker and Lilt presently only supports GIF images; the response you're seeing is probably an attempt at reading a PNG file as a text document. Lilt has this limitation out of a desire to keep its dependency footprint as minimal as possible and therefore make it extremely portable, but I will be fixing the read[] of native-Decker to handle BMP/PNG/JPG soon. Hopefully web-decker or converting your files to GIF is acceptable as a stopgap for the time being.