Is it automatically PNG? Can you draw an entire button

I have made a logo in GIMP for my game ‘SLING’*. I am making all the assets I need BEFORE the actual production of the game. I wanted to ask two questions:

  1. Lets image I design a fish in GIMP. I simply click new, draw a fish and save. WIll it automatically have no background (aka be a PNG) or must you manually remove the white background?

  2. Can you just draw a play symbol in GIMP and import it into cocos2d-x as a button? Giving it the ability to act exactly like a play button.

For gimp questions. Ask them

Yes save as a png and bring into cocos2d-x as a Sprite.

Please read our docs! We talk about everything you asked with the exception of gimp specific questions.

Be prepared to adjust your art as needed once you learn about design resolution.