Adding a picture to a deal has 2 main benefits:
It helps you and your team quickly identify properties in the app.
It prints on your mail so it catches the owner's attention (higher response rate)
You can add a picture when you first create a deal, or after you create a deal.
When you first create a deal, drop a pin on the map and press the plus button to add the deal. Then, click the camera icon beside the owner information and choose "Take photo." (mobile app only)
After a deal is already created, open the deal and click the Camera Icon at the top of the deal (mobile app only).
If taking a picture isn't possible, you could get our Street Pic add-on. It adds a curbside picture to all properties you've added without you having to do anything else.
Hope this helps.