Do your first compression test with dry cylinders, then repeat after squirting a little oil in each one. If the compression comes up from the first test, that's an indication that the rings aren't sealing well on that cylinder. Although you could have good compression numbers and still consuming oil (that one plug sure looks oil fouled) but the oil ring broken and not doing it's job.

Kevin
1951 Chevy 3100 work truck
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1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.