In principle, dark galaxies in the dwarf-galaxy mass range may be detectable through additional, small-scale image splitting of quasars that are already known to be multiply-imaged on arcsecond scales. Here, we derive the image separations expected for dark galaxies with density profiles favoured by recent N-body simulations. The results are compared to the angular resolution of existing and planned telescopes at X-ray, optical, near-infrared and radio wavelengths.