Regarding PS Express.
On an iPad, trying to open a photo from stream taken with my iPhone 6 I get this message:"Photoshop Express is unable to open this file".
No problem opening photo from iPhone 5 from stream or from camera roll.
i had a similar issue. In some apps there's an option for photo quality to use either High Quality or Professional Quality. Professional Quality makes the picture a TIFF format and apparently Photoshop Express can't process a TIFF picture so I had to make it High Quality for a PNG file And the import works now! Another issue some people have reported when using the regular stock iPhone camera app you have to enable Location Services and enable Use Cellular Data, and it seemed to fix your problem also... Hope this helps!