In "make map" mode one big map image is created from selected area and in "download only" mode map tiles from selected area are downloaded to database for offline use. No. When you're moving around in the map all map tiles that you see are automatically saved to database for offline use. If you want to download all map tiles from selected area you can use "download only mode". (There's a bug in the current version that causes Mapsi to crash if map tiles are downloaded faster than they are written to database so you might have to limit download speed if you have fast Internet connection. That is fixed in the next version.)