The easiest way to spread out your photos is to create your post with your uploaded photos in it. Before going "live" with the post click on the "Source Mode" icon. That's the icon on far left end of the toolbar (it looks like two letter A's separated by a slant mark); this will show your photos as . Separate each one on its own line putting a line or two between them. Use the "Preview" button to confirm things look good and then post 'em up!
....