And yet the courts in MN and the state legislature have said that photo only enforcement is illegal.
No it's not the owner's responsibility, it is the responsibility of the law enforcement agency to prove beyond a reasonable doubt that a crime was committed by a specific person.
How can it get simpler? If the LEO witnesses the violation, or the person admits to the violation. If a photo of the violation is not good enough to prove beyond a reasonable doubt, then there is no evidence of a violation.