HB, this is a long standing issue in the program (there are quite a few threads on it in this forum). Many suggestions have been put forth to reduce the occurrence, but no one has a successful answer on completely eliminating the issue. Suggestions I remember are:
 
• If you need to preview to screen, print to PDF instead of to the printer and it always seems to print correctly for the image on any Evo report.  
(just an FYI, it will never or rarely ever seem to show the black box on a print preview, so it's not a good check to use)
• I've had some users say if they don't preview but just print directly to the printer they have more success than not in preventing the black image box  
• Some people have suggested making your image file 300x300 or less
• suggested to try changing the image bit size to 8 or 16bit
• use black and white instead of a color logo.  
 
You can try any or all of these to see what works best to cut down on the black boxes.
 
Hope that helps.

The latest (2016.1) release of Evo has a new EVOERP.EXE that (purportedly) has some changes to it that address this issue,

Quote from Lynn_Pantic on 03/11/16 at 10:30:47:

 
Since that update we have never had a black box  
 
Used to happen 5-10% of the time, only on Traveler Thumbnails for us, never on customer/vendor docs.