1. Choose your favourite photo and resample it to 75 wide by 100 tall pixels. Save as a jpg. Make sure you resample so you have 75x100 pixels. Some applications show the image shrunk but it still contains all 2Mpixels.
2. Go to my preferences
3. Use the personal preferences link in the middle of the page.
4. Browse down to the Portrait field.
5. Use the Browse button to browse for your image created in step 1.
6. Select the image and ok.
7. Save the personal preferences

Congratulations you have now added the personal touch of a company face!