First of all, please ensure that you are using the most recent version of Juicebox-Lite (v1.4.2)
Yes I use the latest version of the library.
If your gallery sets screenMode="AUTO" (the default value for this configuration option), then your gallery should be displayed in Small Screen Mode on small screen devices
screenMode is a pro-Version setting, right? So I use the lite Version and can't set this setting.
Do you see the problem in both Chrome and Mobile Safari on your iPhones or just in one of these browsers?
It looks like the problem exists only in Chrome. I didn't tried it before in Safari but it looks like it works correctly in Safari. The false display is also in Chrome on iOS 7 so the problem lies not in the iOS version.
Are you able to upload screenshots somewhere
Here are two links for the site displayed wrong in Chrome:
www.scr1965.de/sites/default/files/temp/chrome1.PNG
www.scr1965.de/sites/default/files/temp/chrome2.PNG
Here are two links for the site displayed correctly in Safari:
www.scr1965.de/sites/default/files/temp/safari1.PNG
www.scr1965.de/sites/default/files/temp/safari2.PNG
Also, it may help if I could see the gallery in question so please post the URL to your gallery's web page
The link for a gallery which shows the worng display format is http://scr1965.de/erfolgreicher_abend_fuer_den_scr.