Image interpolation stops along center lines

Eyewire Bugs
#1
It looks like the image display is broken up into quadrants, which causes the interpolation to break at the horizontal and vertical center-lines of the image (see exaggeration below). Usually this is easy to ignore, but once in a while there is a small/subtle detail behind the centerline which is more difficult to make out.

#2

This is actually an unfortunate side effect of browsers not allowing nearest neighbor resampling of images. Each slice of grayscale image data you see is actually four 128x128 jpeg images which are rescaled to fit the browser screen. The browser attempts to interpolate within each of the 4 images, but it cannot interpolate between them (causing the boundaries you see). Hopefully in the future CSS will add options to force nearest neighbor resampling of images, but as of right now there’s not a lot we can do about this effect.

#3

Why not just use a single 256x256 image? You could probably even have the client-side reconstruct the complete image if you don’t want to mess with the backend.