Search accepts required and omitted terms, and defaults to "OR" behavior.
By "OR" behavior, we meant that a search for "John Doe" would return all hits for either "John" or "Doe".

To require a term, use "+" (plus); this would ensure we only display images of John Doe, and exclude images of John Miller:
example: +John +Doe

To omit a term, use "-" (minus); this would return all images from John, excluding images of Miller:
example:John -Miller

To search a string of words as if it were a single term, wrap it in either single or double quotation marks:
example:John Doe "Jolly Jumper"

To require or omit a string of words, add the "+" or "-" sign within the quotes:
example: John Doe "+Jolly Jumper"