Map Size?

I created a quick classic looking dungeon map as part of redoing some hand made maps for one of my up and coming play sessions. The map templates I'm working with are 2100x2100 pixels (2100/70=30 squares). When I drag and drop the PNG file onto the virtual table top it does not seem to fit correctly. Is there a maximum resolution size we should be aware of? I've attached the sample image to this post for your reference.

I tried the grid alignment tool, which calculated the grid sizes based on the dragging 3x3 square method as small as 58x58 and as large as 71x69. Never seemed to clue in on the fact it was 70x70. It seems to cut off the right and bottom most five rows of grid if I align the top left corner to the play table.

I had the dimensions right as the tool picked it up when I dragged and dropped the original image. Setting the page size 30 units by 30 units resolved my issues. I often forget about those options being available as I tend to use the page selection mechanic just for flipping pages rather than also locating additional preferences.