You should be able to reference any DLL from a script by including it in using statements, just as when used in a project.
(I have not tested with this lib myself though)
We have plans to (later) add picture handling into the scripting API.
Where do I have to place the library? I tried to put it in the directory of the script where I call, and in the directory of Helium. In both cases it shows the following error:
It's good news that can be done from the scripting API.
I think this might be caused because some reference is not found (might be an external DLL).
The script API in Helium is based on csscript, possibly you can find more information about referencing assemblies here:
Marked as implemented since the script engine supports external libraries.