I found and fixed the web server issue causing images to load slow for one client I knew of.  The issue was that the server was starving for threads, the Apache defaults are not adequate for a larger busier site and we have sufficient machine resources to support a much larger configuration.  Now this customers images load in milliseconds instead of seconds.  The seconds were the time Apache was taking to ramp up processes.  Now the minimum is sufficient to support traffic bursts and it can ramp up to very higher if necessary.