Could you please let me know the exact dot version of Acrobat you are using and the OS running on the system?
Also please attach a screenshot of the issue you facing .
Is the issue same with all the pdfs which you try to download?
From which source you are downloading the pdfs?
I have the Adobe X Pro for Mac & I have the OS X Yosemite version in
Safari. This is a screen picture I see when trying to open some PDFs;
this one is my receipt from Reliant that the images don't appear