Nanospeckle illumination microscopy (NanoSIM) based on disordered metallic nanocomposite island substrates is described. The nanoisland substrates can be fabricated without lithographic techniques. Azimuthal scanning illumination of nanoislands creates near-field distribution that excites an arbitrary number of basis images to produce super-resolution. Experimental studies of point-spread images using NanoSIM with 360 basis images obtained by azimuthal scanning find spatial resolution improved by more than three times with an achievable full-width-at-half-maximum at 81.1 nm on average. The approach is confirmed by imaging aggregated nanobeads and nanoscale distribution of gangliosides on the HeLa cell membrane.