Search Options are a set of features that allow you to refine your web searches on Google. For example while searching you could these options to see for the stories that are published in the past 24 hours or past week etc. These search options are quite useful for refining the search, these options are released few months back for web search. Now Google added these set of features to the Google Images section.
To access click on show options link on top of the search results, the options will show in a left navigation bar. The search options for images includes Medium, Large, Icon, or you can specify a particular size like 1024×768. You could also use type of images options, here you can search for Face, Photo, Clip art, Line drawing. Other options include searching based on color. All these features are available from advanced search pages, but now with the prominent search options line they become more visible and quite useful for refining the search.