They took liberty in the selection, arrangement, edition, and interpretation of the pericopae they knew of. They wanted to paint a different picture of Jesus. The Gospels are written to address the distinct needs of their readers. The Gospels are more like a portrait than a photograph or a piece of abstract art. Remember that authenticity is meaningless in any translation.
All translation involves some interpretation.
The continuity of the four Gospel traditions implies diversity within a recognizable limit. It is meaningless to construct a harmony of the Gospels or to harmonize parallel passages of the Gospels. The Gospels are not biographies of Jesus in the modern sense. Its aim has never been to covey mere historical information. Accuracy and comprehensiveness has never been the sole concerns of the Gospel writers.