Edit the origin image point of the sprite in the animation editor.
construct.net/en/make-games/manuals/construct-3/interface/animations-editor
Image points: display and edit the origin and image points in the image. This switches the color palette pane to a list of image points, allowing you to add and remove image points. The origin determines the rotation point of the image, and is where the X and Y co-ordinates of the object are aligned to.