This is the equivalent of making a photocopy of a photocopy n times for n-1...
You're thinking analog here, not digital. The images will not loose anything if you are using lossless image formats and do not limit the amount of bits available for colors.
An example of limiting the colors could be if you are using BMPs with color depth of 32 bits per pixel for your work and then for some reason save them to GIFs. In this situation there is a high chance that you will loose some colors from the original image, because the GIF format supports only 8 bits - eg. maximum of 256 different colors. The final result depends how much you are using of the available 32 bits in the BMP. If there are more than 256 different colors in the original, data will be lost in the BMP-to-GIF conversion because the GIF has the 256 color palette limitation. In this situation the image processing software usually try to approximate the colors so that the resulting image is as close to the original as possible.
Wikipedia has (as usual) a good article about lossy compressions:
http://en.wikipedia.org/wiki/Lossy_data_compressionThose indeed do work more or less like in your photocopy example, because the compression algorithm is executed each time when the image is being saved to a format with lossy compression. A JPG/JPEG is a good example of this.
Bitmaps are used by computer software internally for rapid access, but usually the images are stored in some compressed format because the raw bitmaps use so much space.
Keep up with the good work oneway with your maps and scenario software, this image format "debate" is just for general advice
And that is enough from me to this completely off topic subject
