1. An imaging reader for electro-optically reading a coded symbol, comprising: a solid-state imager including an array of image sensors for capturing light from the symbol over a field of view; a controller for automatically determining whether an image of the symbol is located entirely within the field of view of the imager, and for processing the symbol only when the symbol image is located entirely within the field of view of the imager; wherein the controller is operative for determining symbol boundaries of the symbol image, and for processing the symbol image when the symbol boundaries are located within the field of view by predetermined margin distances that are selected based on the symbology of the coded symbol.