To find criticism of an artist's body of work:
Artist + critique OR criticism
Sample searches:
Andres Serrano critique OR criticism
Diane Arbus critique OR criticism
To find public reaction to a specific photograph:
Artist + name of photograph + public reaction [other terms: public interest, public opinion]
Sample searches:
"Ansel Adams" "el capitan" critique OR criticism
Joe Rosenthal "iwo jima" public reaction
Eddie Adams "viet cong" public reaction
San Francisco Museum of Modern Art
Specifically: Artists + Artwork, Projects + Perspectives