proper call to static methods

Hi there!
I'm currently developing the NextCellent Gallery plugin and I found current Version NextGen Public Uploader is working fine with NextCellent. I tested the features and it is absolutely great!

The current request is trying to workaround a few issues since I'm working on PHP strict mode. I tried to be sure to call static methods properly without containing $this references.

What I did was simply activate strict mode and modify the plugin until there were no more error nor warnings.
Please notice the plugin was tested with NextCellent, but I didn't tested it with NextGen.

Also , this plugin allowed me to find two NextCellent errors due improper class use.
Please check if the concept is right for you and keep the good work!