It is very simple to use a QR code for students to access a GIF.  Just upload the GIFS to your Drive account and, from there, create the QR code. (If the GIFs you want to link to are already in Drive, you're good to go!) You do have to make sure that anything that you want others to access is set to "Anyone with the link can view". The easiest way to do that is to just create a folder and set the folder to “anyone with the link can view”. Then upload all your GIFs to that folder or if already in Drive drag into that folder. If you already have the GIFs in a folder, just set that folder as “anyone with the link can view” and it will, automatically set all files within correctly. One note: If you are using a school G-Suite account, there is a little trick to setting the files to "anyone with the link can view" if you want others outside of your organization to be able to view. Here's how:

Once you have your GIFs set as "Anyone with the link can view", you can create the QR code. For example, here is a QR code to one of the GIFs in the GIF Collection.

There are a couple of tricks you need to know for getting the QR code.  

One is that after you open the GIF in Drive, you have to go to the "3 dots" in the upper right and choose "Open in New Window" (this is, also, necessary if the file you want to link to is a pdf).  THEN, you get the QR code.  If you are linking to a Docs, Slides or Sheets file, the QR code is created while you are on the file. (Just be careful with a Slides file because if you are on Slide 4 when you create the code, the code will open the presentation on Slide 4.)

I use this extension to create my QR codes: https://chrome.google.com/webstore/detail/the-qr-code-extension/oijdcdmnjjgnnhgljmhkjlablaejfeeb (Just click "Add to Chrome" and it will appear in your toolbar to the right of where you enter web addresses.)

Usually, I just screenshot the code when it comes up, but you can, also, click "Edit this QR code" under the code and it will go to a page where you can "right click" on the code and save it from there.  

If you are creating quite a few codes, it's easiest just to put them in a Slides file so you can print them all at once.  One hint when adding several to a Slides file is to put a text box under each one to indicate what the code goes to or you risk getting your codes mixed up.