As a web developer, it is very common to have the need for an image server. Usually the requirement is pretty straight forward: We need to dynamically re size an image. This is very common when you display thumbnails and regular size pictures in a site.
Personally, I also like to have a single source image; that way, I don’t have to create all the sizes I need before hand. But most importantly, if I need a new size in the future I don’t have to create that new size for all the images I already have.
When working on enterprise environment, people tend consider only solutions by big companies which tend to be pretty expensive. People that can’t afford these solutions try to create the component them selves, which can be very time consuming (if done correctly).