I'm skeptical of available home thc measuring devices.
My tCheck2 was giving outrageously large canabinoid readings.
I suspected it was registering chlorophyll, because I make long soak tinctures.
So I made a near 0% thc chlorophyll tincture from discarded bottom fan leaves
tCheck thought it was over 20% canabinoids.
Mine works as a chlorophyll meter, not a thc checker.
Determining potency using only a photograph, which might vary in quality, is impossible.