I have been encountering this problem for over a year now...
I maintain over 20 projects in RoboHelp HTML. I have numerous
printed document layouts defined. However, in what appears to be
random situations, some of my images do not print. They display
online just fine, but they are not visible in the printed
documentation. Only a blank gap displays where the image should
display. And there is no conditional build tag applied to any of
these images. The reason I think it is random is because, if I
perform the following test, the images print just fine:
- duplicate the printed documentation layout
- remove, from the duplicate copy, all of the pages
surrounding a page that contains an image that does not print
- generate the duplicate copy