As they plot at the printer but not as a PDF then it is obviously something to do with the way they are being plotted to PDF.
Are you 'plotting to pdf' or 'exporting'?
Tutorial (scroll down the page): http://autodesk.blogs.com/between_th...gle-click.html
If you are plotting then do you know what driver is being used?
I have had problems in the past with images not plotting from within Autocad and it turned out to be a driver problem.
The plotter I was sending it to was a Toshiba Laser printer using a .psl2 (postscript) driver.
When I changed it through windows to use a .pcl6 driver the problem was cured.
Last edited by NukeCad; 28-01-2015 at 02:44 PM.
Im intelligent enough to know that I dont know everything; but I'll tell you all about it anyway.