I just installed a new theme (organicthemes.com – natural) and it has the ability to add a logo to the header. everything was fine until i went and accessed from IOS devices. after the page loads the header image disappears as if it cannot be found. I tried changing images, looked at the code, etc…finally I disabled all of the plugins and it worked.
After renabling each 1 at a time i found the membership plugin was causing it to happen. i have went through all of the settings in membership and cannot figure out what could be causing it on IOS only devices.
If i login with my admin account though it does not happen so as of now it appears that the issue could be related to how the public or non-logged in users are treating the image(s).