You talk about the compiler having to be sufficiently smart, but I think you actually just need good IDE support, then you can store the code as text but display a nicer rendering.

E.g. the image literal could actually be Image.loadFromPath("../.../image.png"), but you don't see the code unless you want to; and if you drag and drop a file into your program, the IDE automatically inserts the corresponding code.

Yes, there are probably lots of useful interaction methods to be found in between text files and the "boxes and arrows" visual programming (circuit design) model.