Images rotate automatically - php

Question

I have a iPhone app that uploads pictures to my server. One major issue I am having is a rotating one.
For some reason if I upload a picture from my iPhone, some pictures will automatically rotate. The one's that do get rotated are the ones in portrait mode. I have no code in my script that rotates the images.
How does a server exactly process tall images? Should I modify my php file to check to rotate it ahead after it automatically rotates? Should I code something in my iPhone app that will check this?
Any help is appreciated!
PS: If you need code, feel free to ask!

Answer 1

Some pictures(jpg) have exif data that tells the position the camera was when the picture was shot.
Take a look at http://www.php.net/manual/en/function.exif-read-data.php#76964
You may rotate the pictures server-side like this

Answer 2

Or a better way is to use this library
https://github.com/Intervention/image
And simply use like this-
$img = Image::make('foo.jpg')->orientate();
More can be found here.

Answer 3

When you take a picture your phone saves any rotation metadata in EXIF headers. When you upload the image to your server, that metadata is still sitting there but it's your job to apply it to the image to rotate it (if you want). In PHP you can use a function called exif_read_data:
function correctImageOrientation($filename)
{
$exif = exif_read_data($filename);
if ($exif && isset($exif['Orientation'])) {
$orientation = $exif['Orientation'];
if ($orientation != 1) {
$img = imagecreatefromjpeg($filename);
$deg = 0;
switch ($orientation) {
case 3:
$deg = 180;
break;
case 6:
$deg = 270;
break;
case 8:
$deg = 90;
break;
}
if ($deg) {
$img = imagerotate($img, $deg, 0);
}
imagejpeg($img, $filename, 95);
}
}
}
To use it simply call the function after you save the file. For more info and an additional PHP solution see the original source.