Replacing Many jpgs with tiffs

Hi,

I've got several thousand tiffs that I've scanned in that I'm wanting to replace jpgs that were already on my gallery with. I know that I can replace individual images via the web interface, but I was wondering if there was a way that I could replace thousands of images relatively simply if they are named approximately same thing (e.g. abc123.jpg and abc123.tif)?

Thanks,

Bill