Even though this thread is old I wanted to add that the script on the
knowledge-base article page does NOT fix/recompile image references inside content block controls in a sitefinity page.
If I have a header image that was added with the sitefinity Image control, that WILL be fixed.
If I have a static HTML reference to an image inside a SF content block control, it WILL NOT be fixed and all such references must be corrected manually.
This was not immediately obvious after reading this thread and I thought might help someone in the future.