As I have a Netspark filter on my phone all I needed to do was ask their customer support to block the gifs on WhatsApp and they sorted out the issue. If you have a different filter I would suggest asking them to see if they are able to find a solution. If these aren't options try adding
https://tenor.com/ (the database the gifs are from) to your filter blacklist and see if that helps.
[If none of this works perhpas try getting in touch with TAG [url]
www.taghelpline.org/[/url]]
Good luck!