I'll have to look into that, I setup it up with BI and now I'm confused
I set this up yesterday at this time, and put 1440 in the time. That should have given me a snapshot today at around 11am (Since 1440 mins in 24 hours)
What I got, was a snapshot from every camera right at midnight...
It is described in the help file somewhere, but basically if you put in a nice easily divisible time frame, Blue Iris will align it with the tick of the day/hour/minute or whatever. To get a snapshot at exactly noon, I think you would need to use a 12 hour interval, or 720 minutes. Of course you also get one at midnight then.
BI also has scheduling functions so you might be able to schedule the thing you want to happen at noon every day.