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=2278
However, 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. 
