When adding a photo to a submission, there are two places it could be taken from: either the photo gallery of existing photos or taking a new photo with the camera. Whether a user can pull from one or both places can be determined by the form builder or admin from within the photo field settings.
Configuring Image Source
The setting to specify Image Source for a photo field is located in the More settings dropdown in the left settings panel.
1. On the Forms page, create a new form or edit an existing form.
2. Add a new Photo field from the Fields Library and click on the field to open field settings in the left panel. Or select an existing photo field.
3. Expand the More dropdown and look for the Image Source dropdown.
4. Camera or Gallery is the default which will allow existing photos or new photos to be added to the field. Camera Only or Gallery Only will allow only camera or gallery as the source respectively.
Now when your user adds a photo their device will either go directly to their camera or directly to their photo gallery depending on which setting you chose. If you select Camera or Gallery, then the form will ask the user which they would like to use.