Spilled Paint Effect
Created by: Pedro

Open the picture you want to use as the source and resize it as you like depending on the region you will use. (For the purpose of this tutorial the image was resized to 200x133.)

Leaving the source image open, create a new image and set the background color to the same color you will use in your webpage and approximately the size you will use of the original picture.

Select the clone brush and use these settings:

Shape = Round
Size = 25
Hardness = 100
Opacity = 100
Step = 1
Density = 100

Now minimize the source image and the blank image so you can see both images at the same time. (To make it easier I put one on top of the other.)

Click on the source image to make it active then about the center of the original picture hold down the shift key and right click.

Move the brush to the blank image and draw a zig zag pattern.

Use the magic wand and set the tolerance to zero, click in the background colour then invert the selection (you will end with the picture selected).

Select Effects > 3D Effects > Drop Shadow and use these settings:

Color = Black
Blur = 4 to 6
Offset = 2 to 5

You may try copying the selection to a new layer and expanding, darkening, and blurring it for the shadow, but I think it's way better this way (and easier too).