It's a portion of an Associated Press photo, from the University of Mississippi Digital Collections. The caption reads:
OXFORD, MISS., Sept. 19 -- CHANGING SIGN -- When students entered the main gate at the University of Mississippi in Oxford (Ole Miss) this morning, they were greeted by the sign at left, calling for "white students" to report for registration. Later the "glued-on word" was removed and the sign returned to normal. The campus of 5500 students awaits the arrival of Negro James Meredith scheduled to become the first of his race to enter the all-white university. No one knows when or by whom the word was placed.