this was listed in the 0.7.1 changelog on teeworlds.com, but isn't ingame:
+ scale indicator for selected quads with zoomlevel
+ visualise if images are used by layers
+ added shortcut to create quads in mouse position
+ added image preview in "add image dialog"
Shortcut might be ingame without a tooltip for the keys.
Also there is a new pipette button in the editor that can only copy the color you're pointing to with the cursor, but u can't do anything with it as I tested, I could...