If you create a handout in the journal, you can set the image to be the map, then share permissions with all players and they can open the journal entry with the map in it. They can then click on the image to enlarge it. You can also host the image somewhere (like in your game forums) and enlarge the image there, and copy/paste that into the text field of a handout, and they can see the map in the text area and as they expand the handout, it will expand the map up to the size of the handout borders. I do this all the time. It's a great way for players to be able to see a city map, or world map and you can even put the map key in the text as well (as text or as an image)