Here is the original image. We chose a landscape images because it would contain multiple colors.

Shadows and highlights allow you to add more intense shadows to the image. You can also use the highlights to give a it more brighter look.

Replace color allows you to choose a color on the image you want to change and change it to a different color. (for example I changed all the orange, yellow, and red colors to a green. You can also change the fuzziness to change a certain amount of a related shade.

I gave the image a more warm/ominous tone by changing the sky color. Photo filter allows you to change the overall feel of the image. For example a dark, warm, or cool atmosphere.

I like to think that levels is a mixture of saturation and exposure. The darker you make the image, the more saturation. The lighter you make the image, the slightly less saturated the image gets.

The invert option allows you to change all colors in the image to their opposite or complementary colors.

Exposure is a tad difficult for me to describe. It makes the image much brighter and more vibrant or you can tone it down and do the opposite.

Color balance shifts the colors towards each other to give a neutral feel. In this image you can see that the leaves look more blueish.

Hue changes the type of color for example I changed the blue in the sky to an orange color and the orange colored leaves to blue. Saturation controls the intensity and vibrancy of the color. Having no saturation would leave you with a monochrome colored image.