To use image-based lighting

Open the Environment shader.
Instead of mapping an environment texture to the Background color choose a high dynamic range image reflection map to use in the Image-Based Lighting section. Browse to the HDR image, and choose it.
To evaluate the mapping, ensure that Use Environment (this option used to be called Refl. Background) is turned ON in each shader that you want to use an image-based lighting environment.
Turn on Use Environment in WindowDisplay > Hardware Shade .
As you can see from the following image, all of the shading parameters of each shader affect the appearance of the image-based lighting.
Note that there are two Image-Based Lighting (IBL) environments provided in the shader library, and that most of the shaders in the library have been adjusted to work well with IBL.
After you have loaded the HDR image, you will probably need to adjust the tone of it; since HDR images cover a wide range of lighting conditions, the default selection may not be the look you want. Open the next section of the Environment shader, the Tone Mapping section.

Adjust the Exposure, Saturation, and Gamma sliders to adjust the color, brightness, and tonal range of the HDR image.

Image-based lighting can be used with both Hardware Shade and software Render modes.