Generated thumbnail files empty when using the "#" padding option

[jclemans]

Firstly, thanks for creating this gem!
I just wanted to record an issue I ran into, and based on searches, a few others may have encountered. If I can find the time I will take a stab at finding a fix other than the workaround mentioned below.

The documentation examples I saw show:
thumb: { geometry: "100x100#", :format => 'jpg' }
Which should create a 100 by 100 thumbnail with padding. However, I found that a thumbnail would only be successfully created by removing the #. I hope this helps someone else!