Here are my "sky/grass" and "gradient shape" images. The first is dithered, second isn't. I think dithered is better. I created the gradient in the second myself. Again, it's much easier to manipulate gradients in this program.

Here are my eggs. I didn't make the basket. I decorated the eggs with Wingdings text.

Here are my balloons. I decided to do a bit of a different background. I saved this one as a GIF so you can see some of the image loss.

A picture of the sky. Too dark on the bottom, obviously. Quick Mask and Gradient are great. I ran the gradient from bottom to top.

This is the result. Not a great picture but really shows what you can do to lighten just a portion of the image.