Reference scan DPI

Please help me understand how the reference images scale inside Glyphs.

The manual says: “By default, images are scaled to a size where one DTP point corresponds to one font unit and placed at the origin point of the layer. Consider scaling images before importing them into Glyphs when preparing scans.”

Which I understand as “1/72 of an inch” corresponds to one font unit. So, at 72dpi, this would be 1px, and at 144dpi it would be 2px.

I scan reference images at 3629dpi, in order for 1000 font units to match 7mm. However, if I import my image it appears tiny. I need to convert it to 72dpi (preserving the absolute number of pixels) for it to scale correctly in Glyphs. Is it supposed to work like this?

Set the resolution so that the letter is 700 pt (or whatever you cap height is; point, not pixels) high.