Displaying Picture Attachment in Mashup

Summary

Picture Attachment only visible for Admin User (not being displayed for others)

Content

Hi guys

I have been working on a mashup content requirement recently and we are facing an issue while displaying the profile picture. 

We are able to display the profile picture in the mashup content by concatenating instance URL and FileUrl from PictureAttachment child object in contact.  

But the thing is it is only shown correctly for the admin user. when we are viewing it as a sales rep or service rep we are unable to see the image.

What could be the issue here?

Thanks and Regards