If you want your website to look good, I would suggest brighter, and higher quality pictures - especially on the front page. I had to squint and turn my head to try to figure out exactly what was going on in those pictures.
I know but my co - worker won't let me do anything good, and he think's I don't know.
Not to sound harsh or anything, but if your co-worker has chosen the colour scheme and layout of the site and refuses to change it he simply is the wrong person for the position.