I use irfanview from http://www.irfanview.com/main_download_engl.htm
Very nice program.
I need to constantly convert PDF files to JPG. In the past I have used a program called "Fee PDF to JPG Converter". This worked well but then when I switched to a new computer I downloaded it again and had an issue with popups coming up the whole time. This only stopped after I re-downloaded the browser.
I now don't see any free products with high ratings and reviews that do this job. Any tips?