I decided to assemble a quick montage comparing the best released New Horizons Pluto images so far to several outer planet satellites at low resolution. For the satellites I used Voyager images, except at Saturn, where I used Cassini images. I used two images of each body. In the best New Horizons images so far Pluto is roughly 8 pixels across following stacking and extensive processing (in the original images it is 4-6 pixels). I decided to make the satellites bigger, about 12 pixels across, mainly because soon we'll be seeing better New Horizons images than the ones released last month. In all of these images, where possible, the phase angle is comparable to the phase angle in the New Horizons images. I made no attempts to correct the image orientation (i.e. make north up).

Pluto is known to be a high-contrast body. It is obvious from this (with lots of caveats since I don't know the details of the Pluto image processing) that the contrast is rather big but not nearly as big as on Iapetus. The best satellite analogs in terms of contrast seem to be Dione, Ganymede, Io, and maybe Ariel. Triton exhibits far less contrast than Pluto. It's interesting to note that Ganymede has polar caps that are brighter than the equatorial regions.