Page cant be displayed opening FTP pics

I have an FTP site where I have pictures for my customers to view current promotions and such. My problem is that two people so far are able to access the folders and see the pictures, but when they try to open the pics, they get error:page cannot be displayed. One of the people is the CEO!!!!

Both are running Windows XP and have passive FTP turned off, this is the only way they can access my site!!! thats another issue.

Please help!!
Thanks