What is HashtagImages under CellularData?!

Hashtag images (as I understand it) are those images available in your Messages application that you can send to other people. This is what it is:

#images^*: Find hundreds of trending GIFs to add to your messages.

See this article for details on Messages apps: Use iMessage apps on your iPhone, iPad, and iPod touch - Apple Support 🙂

You don't. If you never insert a hash tag image then it won't grow. You can turn it off in cellular data and it will only update over Wi-Fi.

How do i get rid of it?