API CHANGE #3600 Image no longer has an explicit getURL() method, instead it inherits getURL() from File which returns a relative URL (from r96988)
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@102415 467b73ca-7a2a-4603-9d3b-597d59a354a9