Prevent imagejpeg() from saving EXIF data for images (spec. FileDateTime)
exif, gd, php
Solution
Apparently, GD doesn't like when the path to the input / output file is the same, but the credit isn't mine. To fix, use a new (tmp) file to save the newly created image to:
<?php
...
if(!imagecopyresampled($new_cover, $original_cover, 0, 0, 0, 0, $new_width, $new_height, $width, $height)){
return false; // Could not copy image
}
// Create a tmp file.
$cover_new = tempnam('/tmp', 'cover-');
// Use $cover_new instead of $cover
if(!imagejpeg($new_cover, $cover_new, 100)){
return false; // Image could not be saved to tmp file
}
// Use $cover_new instead of $cover
$file_hash = md5_file($cover_new);
$duplicate_book_cover = $this->find_duplicate_book_cover($book, $file_hash);
if($duplicate_book_cover){
return $duplicate_book_cover;
}
// Use $cover_new instead of $cover
$file_id = $c_consummo->upload_file($cover_new, $filename);
...
Problem
Our server is saving EXIF data to every file saved with `imagejpeg()`. As far as I know, this is not the default behavior (or even possible, from what I've read). But, it is occurring, and due to the `FileDateTime` information being included (and using the `time` of save), it is breaking functionality in our upload/approval system (`md5_file()` returns a different value for the exact same image due to `FileDateTime` always being different). Is there a way to prevent `imagejpeg()` from saving EXIF data for images by default? Server Information - CentOS 5 - Parallels Plesk Panel 10.4.4 - GD Version: bundled (2.0.34 compatible) - PHP 5.3 Code ``` <?php public function upload_book_cover($book, $cover, $filename = NULL, $approved = NULL){ global $c_consummo, $user; $approved = bool($approved, true, true); if(filesize($cover)>5242880){ return false; // Too large; } $max_width = 450; $cover_info = getimagesize($cover); if(!$this->is_valid_book_cover_type($cover_info['mime'])){ return false; // Invalid image type } $width = $cover_info[0]; $height = $cover_info[1]; if($width<200){ return false; // Too small } elseif($width>1500){ return false; // Too wide } $original_cover = false; switch($cover_info[2]){ case IMAGETYPE_GIF: $original_cover = imagecreatefromgif($cover); break; case IMAGETYPE_JPEG: $original_cover = imagecreatefromjpeg($cover); break; case IMAGETYPE_PNG: $original_cover = imagecreatefrompng($cover); break; case IMAGETYPE_BMP: $original_cover = imagecreatefrombmp($cover); break; } if(!$original_cover){ return false; // Unsupported type } if($width>$max_width){ $new_width = $max_width; } else { $new_width = $width; } $new_height = round($height*($new_width/$width)); $new_cover = imagecreatetruecolor($new_width, $new_height); if(!$new_cover){ return false; // Could not create true color image } if(!imagecopyresampled($new_cover, $original_cover, 0, 0, 0, 0, $new_width, $new_height, $width, $height)){ return false; // Could not copy image } if(!imagejpeg($new_cover, $cover, 100)){ return false; // Image could not be saved to tmp file // This is adding *new* EXIF data to images by itself } $file_hash = md5_file($cover); $duplicate_book_cover = $this->find_duplicate_book_cover($book, $file_hash); if($duplicate_book_cover){ return $duplicate_book_cover; } $file_id = $c_consummo->upload_file($cover, $filename); ... } ```