Due to copyright issues, the EPL players won't have their portraits/actual pictures. That applies to most popular teams and players you know. Those who have actual pictures are those from the lower leagues.
You can go here and download player pictures. For example, the EPL one is this one:
http://www.sortitoutsi.net/fm2007/index.php?page=downloads&area=file&fileid=2278However, take note that this was done when the first version of FM07 was out. If you're using the 7.0.2 patch and starting a new game, where you have the "real life Jan 07 transfers" in place, their pictures will either not be there or not updated.
Example: Javier Mascherano of Liverpool.
