Image Blocker is an app to block images in Safari browser from loading. This way it helps to increase loading speed and to save your bandwidth. Instead of hiding pictures, you don't even load them in the first place.
Here is a list of image types that are being blocked once you enable content blocking from Image Blocker:
|Image types being blocked from loading|
|jpg - jpeg - png - gif - tiff - bmp - jif - jfif - jp2 - jpx - j2k - j2c|