[NEW]img: url param thumbnail=fileId to download a different thumbnail for an image
[NEW]img: url param thumbnail=fileId to download a different thumbnail for an image

git-svn-id: a7fabbc6a7c54ea5c67cbd16bd322330fd10cc35@30090 b456876b-0849-0410-b77d-98878d47e9d5

changi67/tiki,tikiorg/tiki,oregional/tiki,oregional/tiki,tikiorg/tiki,changi67/tiki,changi67/tiki,tikiorg/tiki,changi67/tiki,oregional/tiki,tikiorg/tiki,changi67/tiki,oregional/tiki