Add a shadow effect to any image just by setting the effect parameter to shadow (e_shadow in URLs). You can customize the x and y offsets of the shadow and the blurring level. The shadow's color can be also changed by setting the color parameter (co in URLs).

Here's an uploaded image for example:

Below you can see the same image while applying the 'shadow' effect:

The offset of the shadow can be customized by setting the x and y parameters:

You can also control the shadow's blurring level (level range: 0-100, default level: 40)

You can also specify the shadow's color. You can specify the color name:

As an alternative, you can specify the color by an RGB value to match the exact color you need: