why would you block google images? Waste of traffic i would say ..
For some sites, yes, but when people visited, they viewed more than one page, clicked on adverts, or even purchased. But with Google allowing direct access to large images, I had no real choice. It is not a wordpress site, so I cannot use any of the plugins.
I know their layout redesign cost us a lost of images traffic, yet it is a workaround here. With simple tweak i managed to pull ~70% of my images traffic back to my website.
When it comes to .htaccess, Apache etc. then I would be the dumbest in a room full of dumb/lobotomized people.
I used to get 15k/day from google images. After template change this number plumped to 1-2k.
I'd go anything between 10-18k a day. Now 5k - and that includes people coming for the text pages.
So, i tweaked my images a bit and now pulling back ~10k/daily