Using external libraries the correct way

[solidstate1991 via Digitalmars-d-learn]

Up to this day, I have to use them by dragging the source into my 
project. When I tried to import imageformats, the compiler looks 
up for the file imageformats.d and fails to finish the program.

I'm not using command line for compiling, I use Xamarin with 
mono-D instead.