PHP Script for Mobile Image Upload Orientation Correction via EXIF
Working on a responsive website which had image upload functionality I came across some issues with mobile image uploads. When images were uploaded to the website from a mobile device's camera roll they would often be incorrectly oriented, turned sideways, upside down, etc. After a little research I found out this is due to EXIF data attached to the image which records the device's orientation when taking the picture. After a little less research I found PHP's native exif_read_data() function. Here is a PHP function I wrote which reads an image's EXIF data and reorients the image to correct this problem. This function only works with .jpg images since PHP's exif_read_data() only works for .jpgs.
PHP does also have a native imageflip() function which could replace the imageFlip() functin I wrote for this, but it is only available in PHP 5 so I am leaving this code as-is for backwards compatibility.