Does mobipocket 4.8 support JPEG images? Stevenson, Robert Louis: David Balfour
includes a JPEG cover image. It is still possible to force GIF using mobigen, but I can't find such an option in MobiPocket Creator.
The GCIDE gets many of its definitions from the 1913 Websters, but having both is worthwhile. The two were converted to MOBI only a few month apart, but perhaps different versions of Creator were used.