JPG image appears gray in PDF using RGB in PDF Setup Dialog

Are the image rendering problems just during edit in FM (preview/thumbnail images), or in the rendered PDF?

> Using Save As PDF from FrameMaker to generate PDF from book file.

What default printer is configured when you do this?

It needs to be "AdobePDF printer".

What is the workflow intent for the PDF?
If just on-line viewing or end user convenience printing, stay in RGB space.

> In the PDF Setup Dialog, using CMYK option generates a PDF but colors are muted.

Apart from the possibility of a wider problem, you are at the mercy of undocumented uncontrolled colorspace conversion algorithms when you render RGB (which JPEGs usually are) to CMYK. If you really need CMYK, I'd suggest converting the original images to CYMK in Photoshop, and saving them out as CMYK EPS. Import the EPS.

> Using RGB generates PDF with good colors, but one image appears as gray.  This image is a JPG,

In addition to the printer setup issue, various problems can arise from JPEGs: extreme embedded color profiles, using other than 24 bits/pixel (8/primary) esp. indexed color, JPS, MPO, some JPEG 2000 options, JPEG XR, etc. I'd be tempted to just open the original JPG in Photoshop, watch for profile alerts, check/set the color model to 24-bit RGB, and re-save as EPS for import.

Moving to Framemaker