I have had my green mandrin in a 20gal. know for about 4 1/2 years and he is as healthy as can be. I don't even have a fuge, I just have 23 pounds of live rock. Not saying any body is wrong about them needing lots of liverock.
Looks like you might be using a flash. You shouldn't need the flash when taking tank pictures and if you do it will just create a glare and/or ruin the look of the lighting given off by your tank lights. Try taking pictures with all other lights in the room off except for whatever lights you have on your tank.