From what I've seen, WPF images' source is a BitmapSource object while the Resources images are read as bitmap. I've easily found a way to convert images from Bitmap format into BitmapSource format but I believe that running this conversion every time I need an image is just costly in terms of performance and memory consumption (The Bitmaps themselves are static but I guess that the conversion allocates a new object in memory for the BitmapSource).
I thought about holding an in-memory, lazy cache for the BitmapSource objects, that way I will only need to run the conversion once per image. However, I find it hard to believe that this is the proper solution for this issue.
The nature of the application is that the data extends over time and the business objects are never disposed. Therefore, this assumption will only hold in case the implementation will hold static resources for these static images.
I will very much appreciate the proper solution for this issue.