I heard from a customer that they are having problems with a gif image in WordPress, it loads up ok and if you try to access it directly it will display but it doesn't work in a post.
It worked for me though using the following steps
- go to the Dashboard
- create a new post
- press the upload/insert icon (just above the content editing panel)
- upload the file
- insert the original size into the post
- press publish
Here's one of the automatically resized versions, which doesn't animate. It looks like it's the cause of the issue.