Option 1: Proposal pictures

Taking photos at the actual proposal. If the proposal is either something the other person knows is coming, or is a place where a camera can be hidden. we can take photos of the actual proposal. 

Option 2: Use of Props

You can use props such as a chalk board with the words "we're engaged" or "I said yes" written on it. Other props might be, scrabble tiles, the ring (if there is a ring), etc. Typically used to announce the engagement on social media.

Option 3: Family Photos

Having your family involved in the pictures. Whether it's parents, sisters, brothers, children, etc. This option can be added to either of the other options if preferred.