I'm interested in whether it's possible to have some kind of vector representation for node icon images, so that when you zoom in, the icon doesn't get blocky.
I guess one approach might be for the node to support custom drawing of the image. The app could then render the vector icon at the appropriate resolution.
Another approach might be for the node to support assigning the icon to a vector image file such as SVG
The easiest thing would be to use EMF/WMF images instead of PNG/GIF/JPG/ICO et al. Those should scale well, both on screen and when printing. Caution: watch out for EMF/WMF files that have embedded raster images in them, instead of drawing real vector graphics.
I tried years ago to see if I could find some software so that anyone could display SVG in a subclass of GoImage, but I was unsuccessful.
Finally, of course, you could use GoShapes and GoText to implement your own images. But this can be a lot of work.