php resize image on upload

Question

I got a form where the user is inserting some data and also uploading an image.

To deal with the image, I got the following code:

define(\"MAX_SIZE\"         


        

Answer 1

Building onto answer from @zeusstl, for multiple images uploaded:

function img_resize()
{

  $input = 'input-upload-img1'; // Name of input

  $maxDim = 400;
  foreach ($_FILES[$input]['tmp_name'] as $file_name){
    list($width, $height, $type, $attr) = getimagesize( $file_name );
    if ( $width > $maxDim || $height > $maxDim ) {
        $target_filename = $file_name;
        $ratio = $width/$height;
        if( $ratio > 1) {
            $new_width = $maxDim;
            $new_height = $maxDim/$ratio;
        } else {
            $new_width = $maxDim*$ratio;
            $new_height = $maxDim;
        }
        $src = imagecreatefromstring( file_get_contents( $file_name ) );
        $dst = imagecreatetruecolor( $new_width, $new_height );
        imagecopyresampled( $dst, $src, 0, 0, 0, 0, $new_width, $new_height, $width, $height );
        imagedestroy( $src );
        imagepng( $dst, $target_filename ); // adjust format as needed
        imagedestroy( $dst );
    }
  }
}