[Userscript] Derpibooru Image Flip Rotate Buttons

Description  
This script adds buttons to the meta bar that utilize CSS Transform effects to enable horizontal and vertical flipping, as well as 90 degree rotations of images. This doesn’t change the image itself in any way or interfere with downloading (saving or downloading will give you the untransformed image no matter what). It simply changes how the website displays it, so it’s perfect for just ‘effing around or looking at images from different angles without having to save the image first.
 
As with my other scripts, you need to have the uploader info turned on for the script to work (Uncheck “Hide Uploader” under your accounts local settings) as that is where the script places the links.
 
It In Action:  

 
Changelog  
V1.0 – 05/08/2017 - Initial release
 
Download Link  
Download
 
Disclaimer and Such  
Use at your own risk. This script does not store or access any user data. This script has been tested but may not be entirely bug free. Compatibility is an issue with CSS and I’ve done my absolute best to make it work with as many browsers as possible, so if it simply doesn’t work on your machine you’ll have to try upgrading or changing your browser.

Nice!

Slight issue when visiting pages without the #extrameta element: Since it’s null an error is shown in the console. I suggest wrapping everything in an IIFE(Immediately-invoked function expression) and doing this right at the top:
 
var extrameta = document.getElementById("extrameta");   if (!extrameta) return;

oops, i normally do have such a thing (in the form of (if document.getElementById("extrameta"){ } around the entire thing) but i forgot. i’ll fix it when i get to it. i’m taking something of a break right now; thanks for pointing that out =]

Cool, that’ll be so useful for references. Somehow I always find screencaps that are the mirror image of what I need.