1. Save your pivot
2. now save it as a .gif, by clicking the drop down bar, under where you type in the name of it.
3. A simple box will pop up. for best results, uncheck merge. for frame delay, put 6, and shrink frame do 2.
4. Now, go to www.imgur.com and upload your .gif
5. Now right click it, and select "Copy Image URL"
6. Paste the link here, in between
For Pivot 3 Users who can't find the Frame Delay and Shrink option:
Quote from ZedFrame delay and shrink frame are the pivot 2.2.5 options. Pivot 3 didn't exist when this thread was made. I don't think Pivot 3 has the option to change the frame rate so the only thing you need to worry about is the resize, which will depend on how big you made the canvas when you were animating. If you used the default size canvas you'll want to set resize to 50%. Uncheck merge, if merge is checked. "Merge" merges together identical frames if they're next to each other, so at best it does nothing and at worst it messes up your timing.
You shouldn't need to do anything else. If it still doesn't work you might accidentally be saving it as individual images or something.
and paste the link in.