I'm importing map-tiles, which I've set to be 70ppi and are 700x700 pixels. When I import them, I expect them to be 10 units, as 1 unit = 70ppi, however they're all being set to 3 units, and I have to manually set the size for each one, every time I add a new tile. The page scale is set to 1. Is there some other setting I'm missing?