Imagelist stuff

I recently wrote a C# application that did a number of things, including dynamically creating technical diagrams using custom graphics based on user input. Initially, I imported all graphics from files at runtime, but I decided to clean up the code and make the program easier to work with, so I put all the graphics from the external files into an ImageList in a custom library and set "ImageSize" as high as it could go (256x256). The images are okay looking, but still not as good as when I had directly imported them from the files at their original resolution. Does anyone know of a workaround where I get the best of both worlds (not having to drag around external files AND having better resolution)?