Why didn't the apostles recognize Jesus after the Resurrection?
The short answer
Jesus was not merely resuscitated like Lazarus; he rose with a glorified body, which was probably different in some respects but close enough that the disciples eventually knew him. At times their eyes were also miraculously kept from recognizing him.
Jesus was not resuscitated, as Lazarus and others were. His Resurrection was the kind all the saved will share at the end of time: he received a glorified body, as we will. We will know one another in heaven, though we may look different than now.
Likewise Jesus' glorified body was probably different in some respects from his body during his ministry, yet close enough that the disciples eventually recognized him (see John 21:4-7). In one encounter, Luke notes, "their eyes were prevented from recognizing him" (Luke 24:16), suggesting he may have looked the same while they were miraculously kept from understanding who he was for the moment.