Hopefully this image explains it a little better:
[*:279fk2e9]1. Draw the sprite so it is facing to the right[/*:m:279fk2e9]
[*:279fk2e9]2. If you drop an instance on the workspace it will look the same as in the editor[/*:m:279fk2e9]
[*:279fk2e9]3. But you can still rotate instances to face any angle in the editor[/*:m:279fk2e9]
[*:279fk2e9]4. The selected instance in this image has been rotated to 90deg - pointing downward[/*:m:279fk2e9]
[*:279fk2e9]5. For pivoting objects like this, you only need one animation angle:- 0deg, Right[/*:m:279fk2e9][/list:u:279fk2e9]
You can add event code to an object like this to make it point towards the mouse, like so:
[code:279fk2e9]+ System: Always (every tick)
-> Sprite: Set angle towards (MouseX, MouseY)
This will set the angle to the direction of the mouse pointer, so if you put the mouse on the right of the sprite it will set the angle to 0. This is why you should always draw rotatable sprites in such a way that they point to the right.
Hope this helps.