The photo clearly displays ineligible voting.
But, to be the skunk at the picnic, the ineligible vote was cast in favor of...who?
There is absolutely no way to determine which candidate got the benefit of the ineligible votes. It seems a safe assumption that it was Cochrane -- but that falls far short of admissible evidence.
I think if fraud can be shown, in an adequate quantity, the vote will be in enough question to call for a second runoff, regardless of who was voted for.
Does not matter. Illegal votes were recorded so the accuracy of the tally is up in the air. Complete audit is required.
I agree that there is no way to make a claim about any single ballot, but if you have enough of them, then you can let statistics do the work. Cochran got a majority of the votes in that district. Any random sample of ballots that is large enough (1,000 is plenty large) is likley to show the same breakdown, within a few percentage points. If the number of invalid ballots is double the margin of victory, the wrong guy won.
The courts generally look at the probability of harm.
If the victory is by 100 votes and you identify 5 fraudulent votes then it’s mathematically impossible to have harmed the election.
If McDaniel can identify enough fraudulent votes in the election to account for his margin of loss then the probability exists he was cheated.
If I recall correctly, Bob Dornan lost by just over 1000 votes but an investigation turned up a couple hundred fraudulent votes. Not enough to spoil the election though.
McDaniel needs to identify roughly 6,000 illegal voters. If he does, he has a good shot at getting another election.