Soccer51x
i made some screenshots on the steps how to find them
(i am adding screenshots to be more clear)
step one: if you pressed F12 then press shift+tab
http://steamcommunity.com/sharedfiles/filedetails/?id=1330714308
once you pressed shift+tab you should see this
step two: if you look on the bottom left it says "view screenshots". you have to click on it and then you should see this
http://steamcommunity.com/sharedfiles/filedetails/?id=1330714402
step three: on the bottom left of the window you see a button with the word "upload". then theres another window to ask you how you want to upload it. if you did the settings how to upload you gotta wait a bit.
http://steamcommunity.com/sharedfiles/filedetails/?id=1330714479
step four: after its done with loading you should see a small cloud which should say that its uploaded. if you click on it then it doesnt say "upload anymore but "view online"
http://steamcommunity.com/sharedfiles/filedetails/?id=1330714520
step five: if you click on it then you'll get another window of how the screenshot looks like
I hope that i didnt understand you wrong and helped you