As Justin pointed out, it's not so much a program problem, it's a PHP and server limitation. If a user has the ability to upload a bunch of images and your server chokes, it's still going to come back to the developer.
Perhaps a better approach would be to setup a bulk upload folder on the local machine, and write a command line script using one of the free FTP programs. Tell your client to copy all the images into the local folder and execute the script to upload everything in that folder.
If the client doesn't want to do it that way, you can offer to do it for them (more money for you), or show them the prices for dedicated servers. :)