The gallery doesn't separate videos and still photos, everything is just in date order. If you'd like to see just your videos, you can open the 'play movies app' on your phone and click on 'my videos'. This will only show your videos not your pictures. And, if you click on a video to play it, you will see the sharing options in the upper right.
The only way to separate photos and videos in the gallery would be to manually go in and create separate folders and move pics into one and videos into the other. Certainly not ideal though.