How to replace camera?

Not within Aseprite, at least not as a camera, as Aseprite has no concept of a camera.

You have a few options:

  1. If the camera is fixed, you can just make a copy of your document, crop it to the part you want to zoom in on, and export that. The following options are if you need to create camera moves.
  2. Create a viewport reference layer that is always in the same and has the same size across all frames, and use this path-animation script to move your various layers in relation to this viewport to create your camera moves. This method lets you move various objects separately, so you could set up parallax and such. After you’ve done this, make a copy of your document, crop it to the viewport, and export the result. I think you’d need to set up your camera moves like this before you do anything else though, I don’t think this script can animate entire existing animated layers, it just makes extra frames afaik ):
  3. You could use a screen recorder while playing the preview and move either the recorder or the document past the recorder to make your gif. This is a simple method but doesn’t let you have parallax, and it can be challenging to get the timing exactly right.
  4. Export your animation and bring it into an editing software, and do your camera stuff there. Aseprite is not editing software, which is probably why it doesn’t have editing features.