%UserProfile%\Local Settings\Application Data\Google\Chrome\User Data\Default\Cache
paste this in your address bar and enter, you will get all the files
just rename the files extension into the extension which u r looking.
ie. open command prompt then
C:\>cd %UserProfile%\Local Settings\Application Data\Google\Chrome\User Data\Default\Cache
then
C:\Users\User\AppData\Local\Google\Chrome\User Data\Default\Cache>ren *.* *.jpg