Organizing and Editing Your Photos with Picasa: Visual QuickProject Guide

Use the Saturation effect to increase or decrease the richness or density of an image's colors.

Open the picture for editing, click the Effects tab, and click the Saturation icon. The Saturation panel appears.

Drag the Amount slider to set the degree of color saturation. Drag to the left to reduce saturation or to the right to increase it.

When you're satisfied with the effect, click Apply. Or click Cancel if you've changed your mind.

By increasing saturation, you may be able to change an overcast scene into a cheery, more colorful one, for example.