With Photoshop you could also apply the Spherize filter to a picture, and, with a few more changes, get the chrome look. However, you probably want a more impressionist look. In most cases what is needed is a ball with generic reflections, not reflections specific to a particular environment.

The impression of metallic reflection can be achieved through the careful use of gradient shades. Chrome-text tutorials on the web go through great lengths to create those gradients. Some tutorials use the Curves tool to distort a basic foreground-to-background gradient. Others make it even more obscure by prescribing heavy doses of Difference blending.

When I read those tutorials, it seemed to me that if the idea is to create gradations of gray, there must be more direct ways of doing that. For text and other flat surfaces I recommend the creation of a custom made gradient. The tools in the Gradient Creation dialog are very complete, very direct, and very easy to use.

For round surfaces, such as in the case of this tutorial, the alternative is to create a base color and then simply superimpose darker areas with feathered-selection layers. Follow the steps below.

Step 1 - Define the canvas and the main mask

In this example we are going to work with a 300x300 pixels Canvas with white background.

Define the ball shape with the circular selection tool. In this example I am using a ball with 177 pixels diameter. Don't forget to hold the shift key to make the shape perfectly round. Position the circle in the center of the Canvas. Save the selection as "Ball Shape".

Step 2 - The ball layer

Create your first layer; it will define the underlying color and reflection of the ball. Each new step in this recipe will add a layer over the existing ones.

Use the Ball Shape mask to fill the new layer with a light gray. It's up to you decide, based on the particular application for this picture, what will be the correct gray; to start try one with brightness 91. Other high-brightness, low saturation colors you may want to use are blue for sky-reflecting chrome balls and green for copper.

Step 3 - First reflection: bottom

Right now, with no 3D hints, the image doesn't even look like a ball. Distorted reflections will provide the hints. The first reflection is in the lower part of the ball: a reflection of the ball's shadow.

Create a new layer and make a rectangle selection from 0,260 to 300,300. Feather that selection to 5. Fill the selection with black. Deselect. Set the Distort / Spherize filter to -100. Apply it two times. Move the whole layer 18 pixels down. Load the Ball Shape selection, invert de selection and cut the portions of the distorted black band that are outside of the ball.

Step 4 - Middle reflection

To figure out what else besides the ball's own shadow should be reflecting on the ball's surface we need to ask ourselves what is around it. If you stop to think about it, our surroundings can be roughly divided in three areas:
   If you look up, a lighter area which comprises the sky, the windows, or the ceiling lights;
   If you look straight, a darker area with the trees, or the furniture;
   If you look down, again a lighter area, the ground or the floor, reflecting the light coming from above.
Given that we started filling the ball with a light color, we now only need to add the middle dark band. The process to do this is very similar to the previous step. Create a new layer and make a rectangle selection from 0,62 to 300,77. Feather that selection to 10. Fill the selection with black. Deselect. Apply the Spherize filter four times. Load the Ball Shape selection, invert de selection and cut the portions of the distorted black band that are outside of the ball.

Step 5 - Specular light

The specular light is the sharp reflection of a light on a smoth surface. In this example I am drawing a simple spot light, but the reflection of daylight coming through four window panes works well too.

Create a new layer. Draw a small ellipse selection, for example: 25 pixels wide by 44 tall. Rotate the selection by 70 degrees and position it at the top of the ball, to the left side. Fill the selection with white. Deselect. Add an Outer Glow effect to the layer. Use white color, 100% opacity, 7 pixels blur and Normal blending mode. Depending on your version of Photoshop you may have other possible settings to control this effect. Use them to create a reflection of light that has a barely perceptible glow.