I just thought of sharing this simple Tutorial on making shadow on Adobe Photoshop.
We are going to land to bellow image as final image.
Take desired image which you want to use to make shadow, as i took image of a Giraffe.
Now open this image in Photoshop and click on Crop Tool or press "c" to use crop tool, then right click on image and click on"Free Transform".
then make your image little bit small and click on "Flip Horizontal".
Then Click on Move Tool or press"M". Then click on Layers > Duplicate Layer.
Then increase size of the Duplicated Layer, after increasing the size press "Ctrl+U" and decrease all three values to -180. Your image will become Dark as bellow.
If you are happy with it then simply decrease the opacity of the Dark image and enjoy. If not then lets go little further. press "M" and select the half legs of the Giraffe then right click > Free Transform. Now here you have to pay attention, press and hold "Ctrl" key then click and hold left click on the corner and drag it to make it look like its laying on ground
After setting your image, click on the Layer and decrease the opacity of the image.
Again its finished here, but you want to do more then go to Filter> Render > lighting effects and set Lighting Effects as shown in image.
Here goes the final image.
with this above, i hope you can make cool image with photoshop