I'm putting this here since Google locked the thread that inspired me due to inactivity(not obsolescence, inactivity!). Of course I took the answer that inspired me a couple steps further because I'm either irredeemably lazy about this stuff or OCD about finding the most "efficient" method(time and effort, not CPU/Storage), take your pick.
So, starting from Ben Gentle's post here: http://productforums.google.com/d/msg/chrome/ohQqSRvtBfI/yaTbUcuqbScJ
... we get that the Chrome Cache resides at C:\Users\<~User>\AppData\Local\Google\Chrome\User Data\Default\Cache\Images , you have to turn on "View Hidden Files" to get there in Windows Explorer, and the idea to copy the extentionless files from the date being searched to a new "project" folder(I've named mine "Images", and then rename them from the command prompt:
<start button>>><Type:cmd>>><Enter> and then
cd AppData\Local\Google\Chrome\User Data\Default\Cache\Images
rename *.* *.jpg
My method goes a couple steps further:
copy *.jpg *.png
copy *.jpg *.gif
At this point, we are done with the command prompt, so close it.
Back at your "Project Folder" in Windows Explorer, switch to Details View:
<Right Click on empty space in the folder>>><View>>><Details>
Now, we'll add the Dimensions Column for sorting:
<Right Click on an existing Column Title>>><Dimensions>
Then we click the Dimensions column title to sort images by their dimensions. Files that have an incorrect extension will have NO dimensions, so once the Explorer Window has finished the sorting, we can select all of the files that have no dimensions and delete them. They will be conveniently together for two step selection and deletion for the whole lot of them.
At this point you can switch to whatever icon size you prefer and then find your target image from the previews. I recommend deleting the Project Folder when you've copied your target images out.
Some last notes: none of this, beyond finding the cache folder itself, is necessary in Linux, as Chrome does not strip extensions from the cached files under Linux. Time was, IE under Windows didn't either, but I have no reason to care about how IE behaves today. Finally, nothing done here is an exclusive feature of Windows or Chrome. Every single step, GUI or Command Line, has an equivalent in Linux, GUI~GUI and Cmd~Bash.