Can I freeze frame in Fusion?

I have a still frame from a video that I'm already working on and I want to use it in fusion and I don't want to save a frame somewhere else and then bring it into Fusion afterwards so I want to freeze the frame in Fusion itself. Is there a way to do this?

Yes. Use the timestretcher tool and set it to the frame you need to freeze. Be sure to remove the animation curve from the timestretcher (it's active by default to create speedramps)