Here’s a strange one, pointed out by H. at work.

Sometimes, when you search for a specific phrase, Google will return a few small images on it’s main search result. It seems pretty random which ones will or won’t – hey, time for a table (most not found by me!)

Returns images Doesn't return images
limecat;hello kitty darth tater
darth vader;princess leia;chewbacca;yoda luke skywalker;r2d2;hans solo
daffy duck;mickey mouse hong kong phooey; bugs bunny
gollum frodo/bilbo baggins;gandalf
gordon freeman buzz lightyear;lara croft>
kate moss claudia schiffer;britney spears;…
hubble mars rover
wilma flintstone fred flintstone (or barney; betty; bam bam; pebbles)<
the last supper mona lisa; sunflowers; …

What on earth is the logic here? I can only presume that they count the number of image hits, and if it’s above a certain threshold then they return the first few! Incidently, the safe search setting does have an effect – mine is set to moderate.