It appears that the Photos section on the iCloud website has disappeared. Photos on iCloud.com has been the only way to access your iCloud Photo Library from a desktop or laptop since it launched in November. The Photos section is also missing from the iCloud Beta website.
Photos on iCloud.com was never supposed to be the only solution for viewing and uploading photos to your Photo Library from your PC or Mac. A new Photos app for Mac is supposed to launch sometime early this year for OS X Yosemite users. It will give you access to photos taken on your iOS devices, as well as let you upload photos to your iCloud Photo Library.
It's unknown if the removal of Photos from iCloud.com is temporary or permanent.