chown / chgrp of a http owned file after upload

Hiya, I have written as part of my CMS, an image upload system, now when the images are placed in the destination folder, they are owned by httpd.root and I need to get them to be owned by siteuser.sitegroup. I have tried to chmod and chgrp it to siteuser.sitegroup but it gives permission denied errors. Is there any way round this without enabling run as root? Or is there a safe way to do this? Thanks.