Site Audit Pro needs access to your Camera Roll in order to make use of the Multi-Add function. In order to grant Site Audit Pro permission to access the Camera Roll, please follow these instructions:
1) Go to the Home Screen and tap on Settings.
2) Tap on "Privacy".
3) Tap on "Photos".
4) Find Site Audit Pro in the list of apps and ensure it's enabled.
On returning to Site Audit Pro, you should now be able to add photos from your Camera Roll to your Projects.