PureRef

This program is the closest thing to laying out images on a sheet of paper which happens to be on a screen.

The program option to make intangible to mouse might be to allow for tracing through on another program.

Saved as .pur files, these canvases are viewable cross platform but as of 2020-07-13, I don't know how it is saved. However, a file created on a Mac can be viewed on Windows with the layout preserved.