Chest of Colors forum

I am playing with photoshop this weekend trying to learn how to control the light ranges so the color is right. Getting a bit too yellow or blue at times depending if I take the photo at my desk or lightbox. Any one have any surgestions on what sizes they find best for photos for forums and the internet? On my blog I thumbnail them and leave the full photo up.

I found that humans in 28mm look too small when the photo is shorter than 350 pixels and photos larger than twice that are unnecessary.
but it all depends on models and personal preference.