When you press the button to "Feedly-F!", you are calling this style (css file), which simply "hides" from your web browser all the annoying elements that feedly shows each time we are reading content.
If you find an error, or want to help, or know more about this idea, you can go to the feedly-no-img Github repository.
%7B(function(i%2Cn%2Cj%2Ce%2Cc%2Ct%2Ccss)%7B%20css%3Di.createElement(n)%3Bt%3Di.getElementsByTagName(c)%5B0%5D%3Bcss.href%3Dj%3Bcss.rel%3De%3B%20t.insertAdjacentElement('beforeend'%2Ccss)%3B%7D)%20(document%2C'link'%2C'https%3A%2F%2Fcdn.rawgit.com%2FSidVal%2Ffeedly-no-img%2Fmaster%2Fdocs%2Fassets%2Ffeedly-no-img.css'%2C'stylesheet'%2C'head')%3B%20(function()%20%7B%20var%20link%20%3D%20document.querySelector(%22link%5Brel*%3D'icon'%5D%22)%20%7C%7C%20document.createElement('link')%3B%20link.type%20%3D%20'image%2Fx-icon'%3B%20link.rel%20%3D%20'shortcut%20icon'%3B%20link.href%20%3D%20'https%3A%2F%2Fraw.githubusercontent.com%2FSidVal%2Ffeedly-no-img%2Fmaster%2Fdocs%2Fassets%2Ffeedly-no-img.png'%3B%20document.getElementsByTagName('head')%5B0%5D.appendChild(link)%3B%20%7D)()%3Balert(%22Feedly%20'No%20Img'%20ON%20-%20Press%20F5%20if%20you%20want%20to%20turn%20off.%22)%3Bconsole.clear()%7D)()){kind=link}