Do you want to add animated gif images to your blog post or pages? You can simply do it like you do it for any other image but after uploading the animated gif images to your WP media library, you found them just as static images without animation when you see your page/post.
The reason that gif images loses the animation when uploaded via WP media library is that WordPress saves uploads in the media library to several different sizes with default sizes as thumbnail, medium, large which eventually makes the image static. But good news here is that WordPress also keeps the original image as well which is still animated.
How to add Gif images properly in your pages/posts
Add the Gif image using the “Add Media” button in your page/post content editor
So once the image is uploaded in the library, the important thing before adding it to your post/page is to choose “Full” as images size which show the animation as is in your content
Once added to the post you should be able to see the image animation right in the content editor
Hope this helps.