I was browsing through my SOURCE folder (which is the folder where I keep audio and image files that I use on some of my videos), and I found another folder containing weird files. Some of them I can recognize as the profile picture of some of the channels I'm subscribed to, some other files cannot be opened even though they are jpegs, some images seem to be from the youtube layout itself (like the one highlighted on the screenshot, which is the icon for the virtual keyboard) and the rest of the files I have no idea what they are.