They are tiny black lines. The further the camera is the less you see them and they even disappear. That is why the last suit had thicker webbing. It isn't the lighting because the movie will probably look darker than those pics and it isn't just the stunt suit because they aren't going to go in and digitally add black webbing to every frame to make it look like the hero suit.
So on close ups, like the official pic, you will see the black webbing. On shots that aren't 1 foot in front of him, they will most likely disappear. That may also be a budgetary reason. They may have not wanted to go in and digitally add webbing during cgi shots so they made the suit that way so that in distant shots you can't see webbing anyways.