Sleazy Fork is available in English.
Shows just fullsize Image with hotkeys & without pop-ups on many image-hosting sites
added
I updated the script but it still isn't working. (Win 7 -FF 39.0)
how did you update it? I tried latest version from github and it worked in firefox https://github.com/Owyn/HandyImage/raw/413fddc9a972b12f72d369ecf51b6f036a99d5c1/HandyImage.user.js
Yes, it is working now, I must have done something wrong. Thank you very much.
add: fapat.me
http://fapat.me/img-55a3f1911f6da.html