Understanding id-Ugs and id-Uds graph of a nMOSFET
Think about what the first graph means: -



The slope is called gm and is forward transconductance i.e. what small change in drain current you get for a small change in gate voltage. This graph is derived with a fixed bias voltage across drain to source i.e. the FET is operating properly in its saturation region: -



Given that the dotted line in the 2nd picture arbitrarily marks the transition point from ohmic to saturation regions then the two curves are unrelated.