hi mate there is several things that can cause this these are
paper type some are better than others i find kodak to give a bad result.
monitor callibration it may just need calabrating there is plenty of programs on the net that you can download.
the printer can be at fault if its getting a bit old that would cause it as they are not as good as they are now.
if the picture was scanned in it caould be the scanner, i had a lot of problems with mine.
I hope this has helped as i know it can be very upsetting untill you find out what is wrong.
hope you sort it out
Castle