This is not my description, but it's a good one. I've tested the install personally and it works as described.
What is Photoshop CS4 Micro? (Besides Awesome)
Photoshop CS4 Micro, like Photoshop CS3 Lite, is a stripped down version of Photoshop CS4 which retains all features and functionality of the original, making users such as you or me very, very happy. Instead of taking ages to install, it takes about 45 seconds!
There's not much else to say about this. If you don't know what Photoshop is, there's no hope for you anyway. I've been using CS3 Lite for ages, and I've now switched over to CS4 Micro. It is, simply put, wonderful! Fully featured yet incredibly streamlined.