This is the image you'll want app users to scan, and in theory, any image can be made into a target.
There are, however, some best practices:
When scanned, app users will hear the audio of your podcast, commercial, or other uploaded audio file
When scanned, a user will be sent their mail program with your entered email plugged into the To field
When scanned, a user will be sent to the URL you've set
When scanned, a user will be be prompted to call the phone number you've entered
When scanned, users will see the photo you've uploaded
When scanned, app users will watch the video you've uploaded