Sleazy Fork is available in English.
Shows just fullsize Image with hotkeys & without pop-ups on many image-hosting sites
Not sure if I should add support for sites like pixiv or deviantart or danbooru, many people just open images there to see tags & comments plus there are already many other scripts to enhance those sites (like one of mine for pixiv to open all images directly & fullsized from memebers work list - https://greasyfork.org/scripts/108-pixiv-direct-original-image-link )
* animation has a separate page also btw: http://www.pixiv.net/member_illust.php?mode=ugoira_view&illust_id=46221687 (needs to be opened from http://www.pixiv.net/member_illust.php?mode=medium&illust_id=46221687 - it checks for referrer)
Wasn't aware of the other script; Retracted.
Or maybe you'll like Mouseover Popup Image Viewer with the custom rules (paste them in the script config dialog which you can find in the same place as Handy Image). These rules add popups not only for images and thumbnails (mini on mainpage and next/prev on the view page) but also for manga/image-sets in full quality so that you don't have to leave the page with comments and stuff.
Add:pixiv.net
Requesting pixiv add.
eg. http://www.pixiv.net/member_illust.php?mode=medium&illust_id=46320874 should redirect to http://i1.pixiv.net/img-original/img/2014/10/03/11/33/38/46320874_p0.png
However, a linked manga page like http://www.pixiv.net/member_illust.php?mode=medium&illust_id=46320700 should redirect to http://www.pixiv.net/member_illust.php?mode=manga&illust_id=46320700 (check for mode=manga in page source?)
and an animation page like http://www.pixiv.net/member_illust.php?mode=medium&illust_id=46221687 should not redirect at all