Site policy is for the picture to be as up to date as possible. Bon Clay's picture is fine. That is a heroic image of Bon Clay when he was last seen. Also, a picture should focus mainly on the actual character. The image you selected has more Luffy in it than Bon Clay.
As for Eiji Nizuma, the picture you selected for it's replacement isn't any better. It's filled with more text and half his face is covered.