I'm working on an app design for updating item prices at different department stores. Essentially, the user updates the app prices by taking a picture of the actual price and the backend processes the picture and updates the database.
The problem is that I'm not sure how to explain the "picture" button to the user. In my case, there's a button that says "Update price" that, when clicked, will display a modal popup with brief instructions and the actual button to open the camera.
Here's the idea, but I'm not sure if there are better ways of explaining this.
So my question is: is there a better way to explain this to the user? I want to assume that my users are 1) dumber than a bag of bricks, or 2) not mobile power users.
We also have a website that will have explanations, but I don't want the user to have to go to our site for an explanation on the app's camera functionality.

