I'm afraid the main problem with RTF image import lies in the fact that Word normally stores images as Windows metafiles; even plain raster images are formally wrapped into metafile streams. Therefore I'm afraid that to implement RTF image import under Linux, a necessary precondition would be to write a metafile interpreter in U++; while I believe this to be an important step extending the range of U++ usability, it's not a thing I can promise to write tomorrow.