1. A computer-implemented method of editing a source image, the method comprising: causing display of the source image at a graphical user interface; obtaining one or more geometric cues about a three-dimensional scene depicted in the source image, the one or more geometric cues being manually added from user input; receiving user input specifying at least four points in the source image; constraining the at least four points using the one or more geometric cues; determining parameters of a virtual camera based at least in part on the at least four points, the virtual camera being assumed to have captured another image defined by a frame on which the at least four points lie; editing the source image by using the parameters of the virtual camera to obtain an edited source image; and saving the edited source image at a memory.