User Account Profile Picture Windows 7/8 Group Policy

Need to put in place the company logo as the account picture for all users. Using Windows Server 2012. Clients are mostly Win 7 some 8. I've mange to replace the default 'user.bmp' and 'guest.bmp' images with the Company Logo I wish to use but it is not going into effect. I tried to use the setting to force all user to use the default aswell but still no prevail. Instead all that happens is the user just has no account picture when logged in and a blank box before logging in. I have set permissions on the shared file for 'domain computers' and 'authenticated users' to read only. A right head banger for something that would seem so simple. Get it sorted Bill