#SCHEMA
CREATE TABLE ManyToMany (
  img_id INT,
  tag_id INT
);

INSERT INTO ManyToMany VALUES
  (1, 1),
  (1, 2),
  (1, 3),
  (1, 4),
  (2, 2),
  (2, 3),
  (3, 1),
  (3, 2),
  (3, 3),
  (4, 1),
  (4, 3);

#QUERY
SELECT img_id
FROM ManyToMany
WHERE tag_id in (1, 2, 3)
GROUP BY img_id
HAVING COUNT(img_id) = 3;