Deleting/Retrieving Photos from iCloud using iPad

I recently received a message that my iCloud was getting full. I think there are a lot of photos in my cloud that I don't really need. Conversely, there is also one photo that I really want but can't find that I know I had in iPhoto at some point so I would like to find it in the cloud. The issue is that several years ago, when I upgraded my Desktop to a new OS it became essentially unusable. I keep my desktop mostly for situations like this where I need to find old files stored on that desktop or one of its external drives. But I looked recently and the photo I wanted wasn't there and it isn't on my iPad (which I still use all the time) so I'm thinking it is probably in the cloud somewhere. But I can't find a way from my iPad to view the files (photos or otherwise) I currently have in the cloud. I would like to do that, both to delete many superfluous photos and to find one that I would love to retrieve.