Boots to a command line, no desktop installed
400MB download, 2.2GB installed
Desktop with Chrome, VLC, Geany & Thonny.
1GB download, 3.6GB installed
Raspbian full desktop & all apps
Chrome, VLC, Geany & Thonny
BlueJ, Greenfoot, Mu, Node-RED, Scratch, Scratch 2, Sense HAT emulator, Sonic Pi
Minecraft pi, Python Games
(and Wolfram Mathematica but that's missing at the moment)
2GB download, 5.3GB installed
All these apps can be individually added to the bare desktop can by using the "recommended software" program in Preferences, but its often better to start with the full desktop.
Android app - Raspi Card Imager - download and image SD cards - No PC required !