This functionality is in fact in Pharo 5 since a couple of months (I added it during ESUG), but I forget to send the ANN, then probably people does not know it and then is not using it.
This is a catalog command line handler to prepare your images from command line. For example, if I want an image with Seaside3:
./pharo Pharo.image get Seaside3
or if you want a version:
./pharo Pharo.image get Seaside3 —version=3.1.2
since this tool is part of catalog, just catalog projects are available… but I find it very useful for prepare my images (and a lot less verbose than the config command line who is still available for non-catalog projects)