Restarting a background gif animation


May I ask how to make a background animated gif restart every time I return to the same page (#2) ?

I have a prototype with multiple screens (pages) - Pages 1, 2 and 3 in the sample. My task is to have the size of the content stretch to fit the browser window (yet be proportional). Page 2 is ideal for this, but the background animated gif on this page doesn’t restart when i return back to page 2. The same animated gif on page 3 perfectly restarts, but it isn’t a background image, and, for this reason, doesn’t provide the promotional stretching.

I was wondering if there is any way to make the background gif on page 2 to restart, or to make the gif on page 3 stretch proportionally (with 40 px allocated for other UI elements on top/bottom of the screen) ?

Gif animations-pages2 and 3.rp (1.6 MB)

Thank you in advance,