When I read an RTF and write it out as plain text (both with pyth), all of the hex for embedded images is included in the document. As expected, the \pict control group itself is gone.
At the moment, I'm preprocessing these files to wipe out the pict group (hex included) before using pyth, but, of course, it would be nice to avoid that. I'm not familiar enough with RTF versions to know if this is part of the 1.5 spec or a later one. However, these files run perfectly otherwise.
I can send you an example, if needed.