I have the same resizing issue, and I used to just be able to click a different tab and it would resize properly back, but no more. Not sure if it's the recent Windows 10 anniversary update, or the latest Realm Works update, or a graphics driver update (I have an NVidia card) but now I have to close the program and reenter it before the window and fonts resize properly.Which makes smart maps useless, I can't see what I'm doing well enough to edit them.
I would not even use simple pictures anymore either except that you can paste them from the clipboard and avoid the graphics mode change when you browse and attach images normally. Although the copy/paste is also glitchy, you'll often get the "Cannot process an image greater than 30,000,000 bytes in size" even though the image is 20-25 megs in size, not 30. I've found you can only reliably paste an image under 20 megs.
I have the OS fonts set to 175% normal as I have a really high-rez monitor and poor vision. So that's apparently a common factor in these issues, I suspect somewhere in the code that loads the graphical editing there is an initialization bug, as it happens 100% of the time immediately upon engaging that mode. It will also occur 100% if you close Realmworks, then reopen it and the tab is saved where the graphic was loaded, and you switch to that tab.