I've been testing some different ways of compressing images and I think it has potential but am not fully sure if it would be lossless.
By converting bmp's using the RichTextFormat hex-coder I've been able to compress images down to half of what fp8 and bcif could achieve but I have no way of confirming it is lossless since I do not have the tools to extract the bmp's hex data from the rtf file.
It was tested as such:
1) Import bmp to rtf.
2) apply (yuta's) openBWT onto the rtf. (BWT works best on this output)
3) shelwien's sse arithmetic coder.
I'd like to know if it would work as a lossless system but I am skeptical since I couldn't find out much on the hex-coder's properties.