This is not shareware, it is crippleware, meaning you can not fully use the software until you pay for it.
ViewIt's README says "program will remain limited unless you purchase unlocking code."

How am I suppose to fully evaluate this program, when some of its features are off limits??

I think it would be more practical to offer a fully-functioning 30-day trial period.

I just downloaded and installed this, but now I'm not sure I even want to test it.