The ip phones compares its firmware with the load statement and upgrades if necessary so my guess is if you look at the phone and note the firmware level and then set the load statement to be the same it might work. I suspect that CME would only access the TFTP server when it needs it.
If you are worried about the size of the archive simply copy it to your PC and unzip it.
Find the loads statement for your phone and copy to flash. switch on debug tftp events and switch on the phone and note the files not found and copy them from your PC. The 3725 will have internal flash with the IOS and an external flash. You can put flash into the external (Dos Format) so you can copy to and from your PC. Alternatively set your PC up as a TFTP server and copy the files to the router.
Thanks for your quick response, Conwyn
It's a great idea to define the same version of the .loads file and I will try it when i have real phones. Then i will just extract cme archive onto the flash,i haven't done it yet because i just wanted to know if ip phones would boot without them or not.
Thanks a lot for your help, Conwyn