The image handling for XMap is rather ill, at best. I recommend pre-warping your images using GDAL. It will take a little bit of time to learn how to use and get image quality settings to how you like them, but then when you import them into XMap, pre-registered, they look million times better.
Mike (Team Serious '10-'13)
Topo 6-10; XMap 6-8; SA '05-'09; PN Yellow, Orange, Blackse