You can add a photo through the app on your phone under a specific sample / vine / tree…
You can also add a photo from a file on your computer onto the web app:
Go to the ‘Sample’ tab on the menu bar (left hand side), and click on the sample or block that you want to add the photo to.
Then click ‘Edit Photos’ - you then have an option to add a photo - just upload the file you want to add.