Pictures are a great resource in any type of lesson, and learning English as a foreign language is no exception.
Here is a useful post by Larry Ferlazzo with some classic ways of exploting photographs in class: The Best Ways To Use Photos In Lessons
It would be logical for teachers to share a 'virtual' image bank. Talip suggested having a shared repository in the Local Area Network, so that any teacher can upload and store images which can be accessed and shared by other teachers. This would be an idea that could be pursued with the Computer Centre...Talip, would you like to investigate the options?
Meanwhile, here are some sources I have come across that might be useful.