1. A remote instruction system comprising: an annotation forming portion that: overlay-displays a first still frame image of a target taken by an image taking portion, in a display area of application software, the image taking portion having captured the first still frame image from a video signal; displays an edited still frame image in the display area by use of the application software; extracts the edited still frame image displayed according to a difference between displayed still frame images prior to and subsequent to a generation of the edited still frame image; and forms an annotation image from the edited image extracted to project the annotation image onto an image-taken area of the image taking portion by a projecting portion according to an instruction given on the basis of a taken image, and a layout information memory portion that stores image capturing information, including at least an overlay-displaying position of the captured first still frame image in the display area and information from the display area from which the first still frame image is to be captured, wherein the annotation forming portion forms the annotation image by use of a plurality of kinds of the application software executed in parallel.