They are not even kissing in this photo.

In the smaller one Travolta has both feet on the step. Assume this is where a friendly hug took place. Then in the large photo we see him backing down the steps, letting go of the rail and pulling away from his friend as a momentarily awkward position is caught on film.

And I doubt they were in a lip lock just before this either. I don't think the photographer would have missed such a photo opportunity.