Galaxy S6 - MMS gifs not sending? My Galaxy S6 Active (and from looking around online, the Galaxy S6 in general) sends some animated .gifs properly, but others just get sent as a still photo.

I search the web for a gif, find it, and save to my phone.  (For this example, I'm trying to send this gif).  I am able to view in the gallery as a .gif, yay!

However, when I go to send it, and attach - it is a still image (not sure if it's the whole .gif, just not animating, or if it's just the first frame).

Other gifs I can send fine.  I have yet to find a rhyme or reason some work and others don't.  I've seen some comments saying that the Galaxy/Android cuts the file size down when it changes the text to an MMS, and this could be stopping the gif?

Thanks for any ideas.  I'd rather not have to root or install a third-party app..I'm mainly interested in learning if this is just a fact of life for my phone, or if there's a fix.  

Edit: With the two answers below, one partial solution is to use another messaging app.  I tried Google Messenger, and was able to successfully attach a .Gif that I couldn't with the default messenger.  However I still can't send those gifs, it says the file size is too large for an attachment.  I understand that carriers put a limit to MMS size, but I'm 99.9% positive my friend with an iPhone can successfully send the same gif that I am not able to. Hmm.

Edit: April 2016 - While it doesn't really answer the question of the .gifs getting cut down, I downloaded Google Messenger, and it seems to be sending .gifs that the default program wouldn't.  Not a perfect solution, since it involves downloading an App, but it's the best I've found so far.

Edit: March 2017 - while not a solution to the MMS sending/not sending gifs, in addition to Google Messenger, both WhatsApp and Signal work fine with .gif. However I believe it's mainly due to their use of the data plan/wifi which allows for the greater file size to be sent.
I figured out how to send .gif files with my Samsung Galaxy S6 Edge and I'm sure there are others out there that are just as frustrated in their search. I tried downloading several .gif editors like Textra and they just did not work the way I wanted. The one app that I found that works is Google Messenger.

Steps I did that worked:

Downloaded Google Messenger app (free from Google Play Store), use Google Messenger as your default texting software for your device (MMS), google a .gif file you want to send (DO NOT TRY AND SAVE IT FROM THE GOOGLE THUMBNAIL PAGE.  CLICK ON THE LINK TO THE ACTUAL WEBSITE THAT HAS THE GIF ON IT), hard press the moving .gif to save to your phone, open GOOGLE MESSENGER, attach the .gif file to a text message from your gallery (IT SHOULD SHOW AS MOVING ONCE YOU HAVE ATTACHED IT), and hit send!! I hope it helps. Good luck!!!