would like to store my photos online
iCloud has no such facility.
There is no way to work an iPhoto Library online, but there are lost of photo sites like Flickr and SmugMug
There is no Photo storage on iCloud -- you can backup your IOS devices including your photos to iCloud - and you can move photos between devices using PhotoStream - but that is not a storage location -
These Apple documents will explain the iCloud features:
iCloud: Backup and restore overview
iCloud: Photo Stream FAQ
iCloud: Photo Stream limits
iCloud: System requirements
Retrieving data ...