A lot of JPG images work fine, but my customer happened to insert one into a container that just won't appear when using FM's Save As PDF feature. This doesn't work on Mac or Windows, and the problem appears in 14 as well as 15. It appears correctly in browse and preview modes, and it outputs fine when I print to Adobe Acrobat -- just not with FM's own Save As PDF implementation.
Inserting the same image directly on the layout has the same effect. The result of the GetThumbnail() function saves as PDF with no problem.
(And as a total aside, I find it strange that container fields won't display fill colors or borders. Since I tried in a bunch of different themes, my guess is that it is probably a Windows-only issue having to do with how the web viewer works. Still, I'm surprised I just noticed this.)
I can upload the sample of the problem image to whichever TS moderator wants it.