How to Create a Shadow in Photoshop ?

Open your image. Make sure that your image is cut out and on a transparent layer. Name the current layer to your liking. Leave enough room for the intended shadow.

Duplicate the image layer. Open up a new layer, change its color to white, and drag the layer under your image layer. Rename the layer copy to "shadow".

Set the foreground color to black. Fill the copy of the image layer by pressing the CTRL, Shift, and Delete buttons. Go to Filters - Blur - Gaussian blur and set the blur around three or five.

Distort the shadow. Look to see if the shadow layer is active and press CTRL and T at the same time. You will see a bounding box with 8 little squares; see where the light is hitting your image and move around the arrows to the right places. Warp the bounding box by pressing CTRL and clicking on the squares. Move the shadow to fit nicely with the image. When you're done, press enter or press apply.

Activate the shadow layer and set the opacity lower so it becomes greyish, about 70-80% is good. Now copy the shadow layer.

Activate the copy of the shadow layer. Set the opacity of this one low so you will see a gradient going from black to grey and lighter.

Resize the copy of the shadow layer. Make it just a bit bigger than the shadow layer.

Save your image. Save your image to PNG or Make a Gif Image . Saving with opacity will allow you to import your image anywhere.