I use GIMP to export a PNG for engraving. I ensure that the resolution (200 dpi) gets saved in the image file. When I upload it to the Glowforge, the size is way off. Instead of 2.7 inches tall, it’s closer to twice that. How can I get the image to engrave at exactly the right size? What image resolution does Glowforge assume when it ignores what I specified in the PNG? Do I need to use some other file format?