How to add profile image into user profile
In Drupal 6 the, goto solution for this is the Content Profile module which allows you to add CCK fields to your user profile (in Drupal 7, the fields API allows you to do this in core): 


  This module builds user profiles as content (aka nodes), which opens
  the opportunity to use all the powerful modules for content for user
  profiles too, e.g. the Content Construction Kit (CCK). It's intended
  to be simple and useful, but extensible by further modules.


You will also want to install the imagefield module to be able to add an image upload CCK field.