Another tip. If you find a GIF you want to change the start, loop or anything else on, ezgif.com is an excellent free web service for that. That site can even import video clips and turn them into GIFs.
Mine is a Flip 4. Maybe the 3 do not support mp4. Try this app https://play.google.com/store/apps/details?id=com.media.zatashima.studio
It is a gif maker. I used it to convert MP4 to gif before making these and worked fine.
If after trying this still doesn't work, contact me again and I'll try to convert them 😁