1. A method for use in real-time insertion of visual effects in a video stream, the method comprising: i. processing at least one reference image that contains a region of interest, which is to be involved in the video stream, said processing comprising receiving user input for inserting visual effects into said at least one reference image with a desired orientation of said visual effects with respect to the region of interest to thereby form an augmented reference image, and defining a set of at least a few reference features in said at least one reference image; ii. grabbing successive sequence of video frames from said video stream, and processing said successive sequence to generate a corresponding augmented sequence of video frames with said visual effects appearing therein; said processing comprising: selecting at least one frame of said video frames, in which at least two reference features from said few reference features appear, for used as at least one snapshot image, and processing said snapshot image to establish correspondence between at least two reference features in the snapshot image and the reference image and determine a reference transformation between the snapshot image and the reference image; independent of said processing of the snapshot image with said at least two features, applying an independent processing to the snapshot image and to other frames of said successive sequence of the video frames and determining a sequence of transformations between the frames of said successive sequence; and utilizing said determined sequence of transformations and said determined reference transformation to determine an operative transformation between the reference image and either one of said frames in the successive sequence; thereby enabling real-time management of the appearance of the visual effects in the video stream by using said operative transformation for the insertion of the visual effects in other video frames of said successive sequence.