Resize image before uploading PHP

Question

I have no idea how to resize image in PHP, my code is:

for ($index = 1; $index <= 2; $index++) { 

    if (!empty($_FILES[\"pic$index\"][\"name\"])) {
            


        

Answer 1

Keep in mind that the picture you are dealing with is already uploaded on the server. You actualy want to resize picture before storing it in "safe place".

$_FILES["pic$index"]["tmp_name"] is probably /tmp/somepicturesname

Answer 2

Here is the code I'm using to resize images.

In my case I give to the function the original file name and then the thumbnail file name.

You can adapt it for your case very easily.

public static function GenerateThumbnail($im_filename,$th_filename,$max_width,$max_height,$quality = 0.75)
{
// The original image must exist
if(is_file($im_filename))
{
    // Let's create the directory if needed
    $th_path = dirname($th_filename);
    if(!is_dir($th_path))
        mkdir($th_path, 0777, true);
    // If the thumb does not aleady exists
    if(!is_file($th_filename))
    {
        // Get Image size info
        list($width_orig, $height_orig, $image_type) = @getimagesize($im_filename);
        if(!$width_orig)
            return 2;
        switch($image_type)
        {
            case 1: $src_im = @imagecreatefromgif($im_filename);    break;
            case 2: $src_im = @imagecreatefromjpeg($im_filename);   break;
            case 3: $src_im = @imagecreatefrompng($im_filename);    break;
        }
        if(!$src_im)
            return 3;


        $aspect_ratio = (float) $height_orig / $width_orig;

        $thumb_height = $max_height;
        $thumb_width = round($thumb_height / $aspect_ratio);
        if($thumb_width > $max_width)
        {
            $thumb_width    = $max_width;
            $thumb_height   = round($thumb_width * $aspect_ratio);
        }

        $width = $thumb_width;
        $height = $thumb_height;

        $dst_img = @imagecreatetruecolor($width, $height);
        if(!$dst_img)
            return 4;
        $success = @imagecopyresampled($dst_img,$src_im,0,0,0,0,$width,$height,$width_orig,$height_orig);
        if(!$success)
            return 4;
        switch ($image_type) 
        {
            case 1: $success = @imagegif($dst_img,$th_filename); break;
            case 2: $success = @imagejpeg($dst_img,$th_filename,intval($quality*100));  break;
            case 3: $success = @imagepng($dst_img,$th_filename,intval($quality*9)); break;
        }
        if(!$success)
            return 4;
    }
    return 0;
}
return 1;
}

The return codes are just here to differentiate between different types of errors.

By looking back at that code, I don't like the "magic number" trick. I'm gonna have to change that (by exceptions for example).

if (!empty($_FILES["pic$index"]["name"])) {
    $ext = substr($_FILES["pic$index"]["name"], strrpos($_FILES["pic$index"]["name"], '.') + 1);
    $dir = "../gallery/$mkdir";
    // Move it
    if(move_uploaded_file($_FILES["pic$index"]["tmp_name"] , "$dir/img-$index.$ext.tmp"))
    {
      // Resize it
      GenerateThumbnail("$dir/img-$index.$ext.tmp","$dir/img-$index.$ext",600,800,0.80);
      // Delete full size
      unlink("$dir/img-$index.$ext.tmp");
    }
} 

Use move_uploaded_file to move it (recommanded) and then you can resize it and send it to it's final destination. You might not even need the ".tmp", you can use.

    // Move it
    if(move_uploaded_file($_FILES["pic$index"]["tmp_name"] , "$dir/img-$index.$ext"))
    // Resize it
      GenerateThumbnail("$dir/img-$index.$ext","$dir/img-$index.$ext",600,800);