Too often we have users that forget they put something outside a drawing border. Then the CAD worker publishes everything. Some of these end up making the thumbnail very small because they somehow put something waaay outside the border.
Don't ask me how they do it. I've asked and they never remember.
Occasionally information is put outside the border intentionally for one reason or another.
I propose adding options similar to what Autocad has when printing: Extents, Limits, etc. An option to publish ONLY everything inside the drawing border. It should be able to recognize the size of a drawing easily enough.