How to get only photo from webcam without getting video stream?

Question

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Hang up to 50 web cameras on one usb port of the computer through external hubs and, upon request, receive photos from all cameras in 1 second. Since all cameras require their video stream to be in the channel, the task is not solved head-on. A freelancer suggested this solution:

"I can't say anything about 50 cameras per 1 port yet (I'm talking about USB, I suppose)
And for 1 second - it's also unclear, it doesn't matter with USB asynchrony.
You need to test this on real hardware to evaluate it.
One thing is clear - with streaming video won't work that way. It's isochronous mode, not asynchronous.
Either you get a bunch of empty frames, or you wait for each one to sync.
Any webcam can work in "photo" mode.
If your cameras appear as devices in the "Scanners" control panel and cameras" or "Devices and Printers" - this means that they are available as standard MAPI devices (Multimedia API)
And M3W is just webcam standards. In fact, it's just a standard dll.
and all this can work just like that,as you need:
Initialization (1 time at the beginning)
Further in the asynchronous loop:
Device selection by enumerator (camera such and such)
Sent the command "shot"
Hung the callback handler
went to the next. camera.
When the camera works, it will be called accordingly. callback handler, will put the photo in a file or wherever it is necessary.
Everything will be as fast as possible - cameras are not expected, everything is asynchronous."

After receiving the advance, this freelancer disappeared, so I think that all his promises to solve the problem in this way are nothing more than a money scam. However, maybe a respected community knows a way to solve the problem?