It's mostly the mines and pretty much everything except whatever is in the far distance and what looks like one of those just below the surface caves that are all over the desert, is revealed anyway.
Doesn't matter, the picture makes things visible which shouldn't be visible because of a glitch, like an x-ray texture pack. Whether it reveals diamonds or epic caves or not really much I don't think it should be public. Someone else might exploit the glitch before I get there!
Okay, fine. I removed it.
I do have optifine installed, but that's because I need it to deal with the lag and I normally don't have it glitch out like that. I think its lag related.
Ok, I have had the exact same glitch happen dozens of times pr. minute though when I had Optifine installed, and uninstalling it instantly solved the problem. I also have lag spikes and unstable FPS, still less annoying than this problem though. But I'm almost certain it's Optifine and not "lag". It also appears to be related to rendering the world failing, not actual missing chunks which you would expect from lag. Rendering the world is done by the client entirely.
There are settings which you can tweak to fix that, the Advanced OpenGL for example, and the thread for Optifine says to turn off threaded optimization and something else in the graphics card settings, and then theres your computers graphics card itself.
Since the huge mass of cows in one location does cause lag when I'm in the area, I'm fairly certain that its connected to the lag caused by that.
Although, to minimize such lag, I'll probably just breed and then kill most of them off when I want to farm them for leather or whatever.