Exif Data is the partially hidden part of a photo file that most people don't think about when they upload a photo to a service like Dropbox or send a photo to a friend. This EXIF data includes the camera model you are using, basic settings of the camera when the picture was taken, the photo resolution and, if your camera has GPS, the location where the photo was taken.
You can extract the Exif data from image file (Get Exif data from UIImage - UIImagePickerController).
You can also view that data with Preview app on mac. To see go to Preview and click for info for image their you get GPS data for file.
It is correct that the iphone(ipad, etc, i'll just call it iphone from now on) strips exif data. This is also not a bug on the iphone but actually a feature.
One of the main reasons android users don't like the iphone and iphone users don't like the androids, is because the iphone is very limited (in terms of freedom to change, alter, etc). You can not just run downloaded apps, have limited access to settings, etc.
This is because the apple strategy is to create a fail-safe product. "If you can not do strange things, strange things will not happen".It tries to protect the user in every way imaginable. It also protects the user when uploading images. In the exif there may be data that can hurt the users privacy. Things like GPS coordinates, but even a timestamp can hurt a user (imagine you uploading a beach picture with a timestamp from a moment you reported in sick with the boss).
So basically it is a safety meassure to strip all exif data. Myself and a lot of other people do not agree with this strategy, but there is nothing we can do about it unfortunately.
The solution
Update: This does not work.
Luckily you can get around this problem. Javascript comes to the rescue. With javascript you can read the exif data and send it with you photo by adding some extra POST data.
please note: this solution was presented to me by another developer and is not yet tested.