I have FastStone Image Viewer 6.2. When I click on an image and FastStone opens the file, I can see the image, but it seems to freeze the program with the not responding message. It has been doing this for quite some time. Why does this occur?

Also, I downloaded the most current version of the program (ver 7.8) and checked for viruses, and it found a threat (PUABundler:Win32/PiriformBundler). I suppose that I shouldn't be converned about this found threat, since I am downloading the program from Faststone.org website?