Site Optimization: PHP Function to Resize and Compress and Reduce Image Quality

As You can see from Waploaded's google page speed and optimization insight, our mobile score is about 75-79 and our Desktop is also about 75-79 That shows how fast this website is, and which also means a good user experience.

Remember images users most resources in a website so there is need for all images on your website to be Optimized properly, in this short tutorial i will show you how to Resize and Compress and Reduce Image Quality.

PHP Function to Resize and Compress and Reduce Image Quality

PHP Code:

<?php 

function waploaded_resizer ($file,

                              $string             = null,

                              $width              = 0, 

                              $height             = 0, 

                              $proportional       = false, 

                              $output             = 'file', 

                              $delete_original    = true, 

                              $use_linux_commands = false,

                                $quality = 100

           ) {

      

    if ( $height <= 0 && $width <= 0 ) return false;

    if ( $file === null && $string === null ) return false;

    # Setting defaults and meta

    $info                         = $file !== null ? getimagesize($file) : getimagesizefromstring($string);

    $image                        = '';

    $final_width                  = 0;

    $final_height                 = 0;

    list($width_old, $height_old) = $info;

    $cropHeight = $cropWidth = 0;

    # Calculating proportionality

    if ($proportional) {

      if      ($width  == 0)  $factor = $height/$height_old;

      elseif  ($height == 0)  $factor = $width/$width_old;

      else                    $factor = min( $width / $width_old, $height / $height_old );

      $final_width  = round( $width_old * $factor );

      $final_height = round( $height_old * $factor );

    }

    else {

      $final_width = ( $width <= 0 ) ? $width_old : $width;

      $final_height = ( $height <= 0 ) ? $height_old : $height;

      $widthX = $width_old / $width;

      $heightX = $height_old / $height;

      

      $x = min($widthX, $heightX);

      $cropWidth = ($width_old - $width * $x) / 2;

      $cropHeight = ($height_old - $height * $x) / 2;

    }

    # Loading image to memory according to type

    switch ( $info[2] ) {

      case IMAGETYPE_JPEG:  $file !== null ? $image = imagecreatefromjpeg($file) : $image = imagecreatefromstring($string);  break;

      case IMAGETYPE_GIF:   $file !== null ? $image = imagecreatefromgif($file)  : $image = imagecreatefromstring($string);  break;

      case IMAGETYPE_PNG:   $file !== null ? $image = imagecreatefrompng($file)  : $image = imagecreatefromstring($string);  break;

      default: return false;

    }

    

    # This is the resizing/resampling/transparency-preserving magic

    $image_resized = imagecreatetruecolor( $final_width, $final_height );

    if ( ($info[2] == IMAGETYPE_GIF) || ($info[2] == IMAGETYPE_PNG) ) {

      $transparency = imagecolortransparent($image);

      $palletsize = imagecolorstotal($image);

      if ($transparency >= 0 && $transparency < $palletsize) {

        $transparent_color  = imagecolorsforindex($image, $transparency);

        $transparency       = imagecolorallocate($image_resized, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);

        imagefill($image_resized, 0, 0, $transparency);

        imagecolortransparent($image_resized, $transparency);

      }

      elseif ($info[2] == IMAGETYPE_PNG) {

        imagealphablending($image_resized, false);

        $color = imagecolorallocatealpha($image_resized, 0, 0, 0, 127);

        imagefill($image_resized, 0, 0, $color);

        imagesavealpha($image_resized, true);

      }

    }

    imagecopyresampled($image_resized, $image, 0, 0, $cropWidth, $cropHeight, $final_width, $final_height, $width_old - 2 * $cropWidth, $height_old - 2 * $cropHeight);





    # Taking care of original, if needed

    if ( $delete_original ) {

      if ( $use_linux_commands ) exec('rm '.$file);

      else @unlink($file);

    }

    # Preparing a method of providing result

    switch ( strtolower($output) ) {

      case 'browser':

        $mime = image_type_to_mime_type($info[2]);

        header("Content-type: $mime");

        $output = NULL;

      break;

      case 'file':

        $output = $file;

      break;

      case 'return':

        return $image_resized;

      break;

      default:

      break;

    }

    

    # Writing image according to type to the output destination and image quality

    switch ( $info[2] ) {

      case IMAGETYPE_GIF:   imagegif($image_resized, $output);    break;

      case IMAGETYPE_JPEG:  imagejpeg($image_resized, $output, $quality);   break;

      case IMAGETYPE_PNG:

        $quality = 9 - (int)((0.9*$quality)/10.0);

        imagepng($image_resized, $output, $quality);

        break;

      default: return false;

    }

    return true;

  } ?>

• 
  Put The above Snippet and your functions file or in the page where you need this resising
• Use The Below Short snippet to perform the resizing

PHP Code:

<?php 

$picToRezise = 'The full Url of the picture to reize';

$height = 'Height of the new picture e.g 350';

$width = 'Height of the new picture e.g 350';

$storePicPath ='the storage path to your server';

$imageQuality ='image quality range from 0 - 100 // the lower the quality the lower the size';

waploaded_resizer($picToResize , null, $height , $width , false , $storePicPath , false , false , $imageQuality ); ?>