Convert files from RSA 503A

I'm having issues when converting files from my RSA503A. After converting files using Adobe/GIMP, I've noticed a significant reduction in clarity/resolution when viewing it on RSA Map, and I'm wondering if this is normal. If not, what could be causing this issue

Are you importing an image to use as the map? If so I would advise using openstreetmap or other similar programs for map data. This provides two advantages. Firstly, you will not loose resolution, and second it will automatically be a geo-referenced map.
We generally recommend calibration once per year, or if the unit fail.
http://www.openstreetmap.org/