The images directory has been missing from the Fedora 21 mirrors.kernel.org::fedora/development/21/x86_64/os for quite a while.
Meanwhile my omen.com server has not been able to yum update since following the instructions on updating the yum groups.
BTW Is there a name for Fedora 21 yet? It has been running so smoothly (modulo yum) I thought of "cuspy".