There are two problems with the N900 Camera:

1- Images in general have slightly less warm colours compared to the N97 and the N95 8GB, which produce beautiful vivid images. The actual display on the N900 has a more warm colour tone than those pre-stated phones (e.g. display the same image on both phones, colours on N900 are deeper and warmer), so perhaps Nokia was compensating by making pictures less warm so they look NORMAL on N900. I tried to manually fix it with the settings, but it is not good enough. Images need more colour saturation and less whiteness. This is essentially a software issue.

2- Apparently due to something with the cover, images have a blueish-greenish tint when taken with Flash. Note that the N97 has the SAME blue-edged cover but I noticed no problems with it though. Perhaps better design. Some people blame the silver Chrome-ish border of the Camera for reflecting light and causing the effect.

Response:

I think only a concentrated effort and mass emailing to websites such as CNET and GSM arena would create enough coverage to embarrass Nokia into changing the covers! How about we do that?

As for non-flash images, better software for image management or using the same colour palette as N97 an N95 8gb for image taking would be the right move. The 3 cameras are supposedly identical.

use search please

.edit
one thread from many
http://talk.maemo.org/showthread.php?t=36675

..edit
I agree that in some sitsuations images might be bad but terrible?
http://talk.maemo.org/showthread.php?p=571278

terrible is putting it lightly
you can tweak and tweak all week till you cant speak and your n900 photos will stil be weak!!!!
this camera is trash and nokia wont lift a finger to change it cause it would be too expensive to come up with some kinda hardware change for every one who brought one

so proud of my self for this rap. WATCH OUT 50 CENTS!!!