Canvas Size

The canvas is the visible area of the sprite. You can change the canvas size using Sprite > Canvas Size... menu.

Canvas Preview

In this window you can change the Width or Height manually, or using the blue rules in the editor window.

Crop

You can change the canvas size using the current selection bounds:

Crop Preview

Trim

You can remove transparent borders from canvas automatically using the Sprite > Trim menu.

Trim Preview