Outgoing Museum of Fine Arts director Malcolm Rogers bid farewell to the public Wednesday night at Cheers to Malcolm!, a celebration of Rogers’s 21 years at the helm of the MFA. Rogers, who will step down at the end of July, spent the evening greeting visitors outside the museum, scooping free Rogers-themed gelato (Never Vanilla Malcolm, anyone?), and greeting well-wishers. “Thank you all and the people you represent for making my time in Boston so stimulating, so exciting, so much fun,” Rogers said to the assembled crowd. “I hope to see you many more times at the museum that I love.’’ A small protest gathered near Monet’s “La Japonaise,” where visitors were invited to pose wearing a kimono (“This is Orientalism,” read one sign), but it did little to dampen Rogers’s spirits. “A little controversy never did any harm,” he said.