Struggling with FITS images in Astrometrica

[Breakintheclouds]

I wanted to have a go at spotting asteroids, but am struggling with getting images into Astrometrica for processing. I'm capturing video images to FITS files using wxAstrocapture, which goes fine. However, wxAstrocapture will only allow me to store them as RGB images, which Astrometrica can't read, so I have to change them to greyscale, using ImageVIEWca. The issue is that although this process all appears to go just fine, the images are heavily messed up when I load them into Astrometrica.

If you look at the two images I've attached, you can see exactly the same FITS image opened in ImageVIEWca and Astrometrica. It should look identical, but as you can see, it isn't. Does anybody know what's going on? Is it something to do with the image depth, e.g., is one program working in 16 bits and the other 8? I'm totally stumped.

[Glider]

The images are flipped vertically and the bottom one looks like it has been automatically stretched and adjusted as it was loaded.