lighting - What should be considered for employee photos to put on company's website?

I work in the entertainment industry and am looking to produce friendly looking images of our employees (sales managers, customer support people, and so on) to put on our company's website.

1. What things should I be considering in order to get the best pictures possible?


2. I have a "canvas" of 203×227 (width×height) and image on canvas would be 152×157. Currently I have different sizes of images. What would be the best way to make images that fit well into that image size, aspect ratio with respect to the image size (i.e. 152×157)?


3. What should the background/lighting of the image be?


4. Any advice, hints etc.?