1. A method comprising: receiving an image of a portion of an object of interest from a client device for serving as a reference image; receiving a preview image of another portion of the object of interest; generating a user interface including the preview image; adding to the user interface a progressively growing mosaic preview, the mosaic preview including a thumbnail representation of the reference image; comparing dynamically the reference image with the preview image to determine whether an overlap between the reference image and the preview image satisfies a predetermined overlap threshold; and responsive to the overlap between the reference image and the preview image satisfying the predetermined overlap threshold, setting the preview image as the reference image.