http://pharo.org/download says...
"To run Pharo you need an image(1), changes(2), and a sources
file(3), as well as a VM(4) for your platform."
...then below links to (1) (3) & (4).
but (2) seems to be missing. So I suggest the
"Pharo 4.0 image" link be "Pharo 4.0 image & changes"
And some optional word-smithing on this: "To run Pharo you need
platform independent image, changes & sources files, and a platform
specific VM."
cheers -ben