I keep track of all Assets, Plant and equipment and recently made up a list of items that we are tendering.
Rather than clog up the database with images, I used the link to folder method.
When I am in report view, all the photographs appear nicely, but when I switch to print preview some of the images disappear.  
To get around it I did the unthinkable and used the Attachment feature and everything worked.
Just wonder if someone else has had this issue and what you did to fix the issue. I suspect it is something to do with the Image sizes.