One of my favorite features (so far) of Picasa 3 is the Effects tab where you can apply 12 different effects to your pictures, creating different color tones, shading, etc. You probably can't see it on these photo's because they're too small but you also have the capability to add text to pictures and you can position it any way you want, on a diagonal, vertical, etc. On my 6 photo's below, in the lower right hand corner, I labeled each pic with the effect I applied.
The first row going left to right are: the original pic; Sepia effect which is a certain color tone; and the saturation effect which is a real fun one to play around with.
The second row going left to right are: Focal B&W effect where you choose where on the picture you want the patch of color applied to a copy of the black and white pic, neat affect; the tint effect; and the graduated tint (feather and shade)effect, another neat affect.
I am having fun fun fun with this...