I see this as an s-trap that has an added sewer vent. It looks to me as OK. Does anyone think I am wrong, if so what reason. the home is a 1949/remodel. Thank you.
I would just call out the S and recommend a plumber.
Does everyone looking agree with Tallen, I’m not sure I do. Any plumbers?
This would be a wet vent which in some area’s are illegal. The S trap of course is not legal. The dishwasher drain also comes in below the trap and this should be above it and should be snaked so it is above the bottom rim of the sink. To me, It needs a lot of work to make it code compliant. A plumber is needed.
Not a plumber but I agree with Tallen… call it out and rec. a plumber.
I agree with Tony…
Any other opinions ???
I agree with Jeffrey who agrees with Tony which includes as a subset, agreeing with Robert who was agreeing with Todd.
Ah heck folks make it easy, call out the obvious and refer to an expert.
It is like looking at a bad electrical panel, 10 things wrong, you point out the most obvious and refer to an expert. CYA
Exactly what we all said !!! 
The kithen sink drain line includes an S trap and poses a hazard( long explanation) I recomend that you contact a licenced and qualified plumber for estimates of repair.
It is possible that an expert will find other problems with the instalation that I did not report. “big long explanation here” bla bla.
That whole thing is a friggen mess. No way does any part of it comply with model codes.
S-trap - improper (just not allowed)
Vent location - improper (must be closer to the height of the trap weir - except for a “vertical-leg” type)
Dishwasher drain line - improper (no highloop or air gap)
Dishwasher drainline - improper (must be above the trap)
and I ain’t no plumber neither 