If you want player pictures from the current season for use in the game, here is a link and description of how to import them, courtesy of Strat Fan Forum:

The set is available under Current Season Photo Packs at:
http://my.opera.com/WenKen/blog

Be aware that this photo pack does require the use of an alias file. For those using a photo pack for the first time, please follow the instructions below.
1. Download the batters pictures and open the folder.
2. Copy (click on a picture, Control-A, Control-C) the CONTENTS or PICTURES of the batters and paste (Control-V) them into CDROMBB/Player/Batter.
3. Download the pitchers pictures and open the folder.
3. Copy (click on a picture, Control-A, Control-C) the CONTENTS or PICTURES of the pitchers and paste (Control-V) them into CDROMBB/Player/Pitcher.

Please note that you must open/extract the folder that you've downloaded. You must either see the names of the players or the pictures of the players before you copy them. The most common mistake is that people copy the ENTIRE FOLDER into their Player/Batter or Player/Pitcher folder. Instead, you must be copying the individual pictures into the folder.

4. Download the alias file.
5. Highlight the LINES (Control-A) of the alias file and copy (Control-C) them.
6. Open the alias file in CDROMBB/Player.
7. If this is the first time you've used an alias file, delete the sample lines about Sandy Alomar.
8. Paste the LINES (Control-V) at the end of the alias file. If you've just deleted the sample lines, then you will be pasting the new lines at the beginning of the alias file.
9. Save the alias file
10. When you play the first game, there is a check box for displaying the pictures. It is found in Options/Game Screen Layout. This box must be checked in order to have the pictures appear. It is possible that the batters pictures will overlap the pitchers pictures. You will have to drag the pictures to a place where they can be displayed in a pleasing manner.