I have Paint Shop Pro (which is actually owned by Corel now)... An application to use really wasn't the question.
I am specifically asking about which Lossless file formet would be best for subsequent image manipulation. I can have them save in Lossless JPEG (4300 X 3200 image is ~26 MB) or TIFF (same image is ~30MB).. I don't know how large PSD at that resolution is. These are not Layered images and they do not need to be. I do not need to edit the image except for cropping, resizing and optimizing. With Paint Shop Pro, I can take the same Lossless JPEG and save it with relative clarity at the sizes I needed...
For example, look at www.returnofwhitebuffalo.com, both the painting in the header and the book cover are two such images that I was given at large resolutions. Both came from 25 MB files or so and I was able to reduce them significantly with Paintshop Pro.
So the question at hand is will I get better results from an image format other than Lossless JPEG? File size doesn't matter. All file exchanges are done on Rewriteable CDs and I only get a few images at a time, around a dozen or so.
p.s. Microsoft Paint will not load these files. It doesn't understand Lossless JPEG.
TIFF isn't anywhere near being the best graphic format (especially for merged images).
Since it's already in conventional JPEG (which isn't lossless even at 100%) converting it to another format is useless, the image quality is already destroyed. Either start with a lossless format, or just stick with what you have.