After many days of troubleshooting, I have found the issue and I think it is a bug that could use a fix (hopefully it's an easy fix). When viewing a image in a Wordpress Gallery or Next Gen Gallery that has a long title, ALT tag or description defined, this will cause the height of the PrettyPhoto pop-up window to exceed a certain size. When the designated size is exceeded, the iPhone will not load the photo in portrait or landscape mode. The symptom you will see is the "loading" animation and Safari on iOS basically freezes.
To get around this, I have to do three things:
1.) Disable the image title: To do this, add: show_title: false to line 835 of js/avia.js which loads the PrettyPhoto application. My revised line looks like this:
elements.prettyPhoto({ show_title: false, slideshow: false, deeplinking: false, overlay_gallery: false, default_width: ww, default_height: wh });
2.) Keep image descriptions as short as possible. I found keeping them under ~68 characters seemed to help, but if I have a long word that is forced to go to a new line, 68 characters may be too long. If you choose not to disable the title as described in step 1, then your description must be even shorter since you only have a predetermined amount of pixels to use between the title, image and description before it breaks.
Is it possible to implement a patch that would truncate long titles and descriptions when displaying images on smaller devices? When displaying images on larger devices (e.g. iPad, Desktop), this is not an issue since the since you have a larger amount of screen real estate available to you.
Thanks in advance for your help.