We describe an image-processing technique through which we improve the chances of identifying image features representative of supernova remnants, the last stage of the life cycle of a high-mass star. Supernova remnants have a unique imaging signature, a high Hα to [SII] flux intensity ratio, the detection of which requires accurate continuum-subtraction of the narrow-band images. Since the success of this approach is highly dependent on the images having similar point-spread functions, the effectiveness of this procedure is greatly improved by matching the respective image point-spread functions before subtraction. We apply this technique to archival survey data of a Local Group Galaxy and discuss some issues regarding its most effective use. We present some initial results of our image processing procedures, and discuss some future applications.