RedleX has released Mellel 3.3.3 with a number of user-requested enhancements and bug fixes. The word processing app now displays recent fonts in the Font menu (found in the Character palette), adds an option to control the resolution of converted vector images when exporting to RTF, improves the display of Auto-title, reduces the height of bibliography style mapping window to fit better on smaller screens, fixes a problem that prevented reference elements in the text from being found, and squashes a bug that caused a hang when exporting documents with large PDF or PICT images to an RTF file. ($39 new from RedleX and the Mac App Store, free update, 101 MB, release notes, 10.6+)
I just tried with the new Mellel update to export a file with an image to rtf and it hung. Once I deleted the file, it exported instantly.