A few months ago I enabled the "Full Size" upload option on my Google+ sync for photos. I then realized that I would soon run out of storage and I deselected the option, allowing a resizing to 2048px, which gives me "unlimited" storage (not really unlimited, but you get the point), as only photos over 2048 x 2048 pixels and videos longer than 15 minutes count towards your storage limit. (doc. source)
I was at a healthy 7GB of storage, then today Google+ went completely crazy and said I was using 15.8GB of storage, and had to buy the 100GB option to be able to even send and receive emails.
I looked at the documentation online (BTW, it's totally broken and full of links that end up either nowhere or in the wrong place) and nowhere does it say how I can find the large files in my Google+ photo stream so that I can delete them.
I downloaded Picasa hoping that I could find those files from Google+, sort them by size, and delete from the Desktop app, but had no luck.
I don't want to keep paying for the 100GB (I really don't need them), and I'd like to find a way to identify the big files on Google+ so I can delete them and get back to the 7GB range.