Upload Chatter profile pic using Visualforce Pages

its very straight away andn no more coding required, check below code

<apex:page showHeader="true" sidebar="false">
  <apex:form >
  	<chatter:userPhotoUpload showOriginalPhoto="true" />       
  </apex:form>
</apex:page>

output

Hover above smiley and click it then following screen will appear

Happy coding!!!