Upload picture and create thumbnail with PHP

This page will teach you how to write a code in php for uploading picture and create thumbnail.

With the class below, you can specify

  • Max file size for upload
  • File types that allow for upload
  • Upload path, and thumbnail path
  • Either create thumbnail or upload only
  • Set thumbnail dimensions
  • Mode on creating thumbnail - exact (default), stretch, or crop

This tutorial requires 3 files to process: form.html, upload.php, imageUpload.php. You can copy and paste the source code below and test on your server.

Example html file "form.html" with form upload

<form action="upload.php" method="post" name="uploadform" id="uploadform" enctype="multipart/form-data">
<input type="file" name="my_upload" />
<input type="submit" name="submit_btn" value="Upload" />
</form>        

when the form is submitted, file "upload.php" will be process on server. The source code of file is as below

<?php
//include a class require_once("imageUpload.php"); //how to use a class
$upd = new imageUpload("my_upload"); $upd->setUploadPath("./pictures/"); $upd->setThumbPath("./pictures/thumbnails/"); $upd->setCreateThumbnail(true); $upd->setThumbDimension(100, 100); $upd->setMaxFileSize(5242880); //in bytes, around 5mb $upd->setThumbMode("crop"); $image_uploaded = $upd->uploadImg(); if($image_uploaded !== false){ echo("File uploaded"); //proceed database }else{ if($upd->isUploadError()){ //show errors $msg = $upd->getUploadMsg(); print_r($msg); }else echo("Oops! unknown error"); } ?>

PHP class for upload picture/image named "imageUpload.php" is as below

<?php
class imageUpload{
    var $upload_err = 0; //upload status
    var $upload_err_msg; //for keeping upload error messages
    
    //set limit upload filesize in bytes or zero if no limit
    var $max_filesize;
    
    //set allow type (mime type)
    var $allow_type;
    
    //set paths
    var $upload_path = "examples/pictures/";
    var $thumbnail_path = "examples/pictures/thumbnails/";

    //sometimes uploaded filename may contain special characters and to prevent read/write problem, you need to change it.
    var $set_name;

    //assign default thumbnail properties
    var $create_thumb = true;
    var $thumb_width = 200;
var $thumb_height = 200; var $thumb_mode = ""; //exact (default), stretch, or crop //field name on form var $fieldname; //initialize class function imageUpload($fieldname){ $this->fieldname = $fieldname; $this->max_filesize = 0; $this->allow_type = array("image/pjpeg"=>".jpg", "image/jpeg"=>".jpg", "image/gif"=>".gif",
"image/png"=>".png", "image/x-png"=>".png"); $this->upload_err_msg = array(); $this->thumb_width = 0; $this->thumb_height = 0; $this->set_name = ""; } function setUploadPath($path){ $this->upload_path = $path; } function getUploadPath(){ return $this->upload_path; } function setThumbPath($path){ $this->thumbnail_path = $path; } function getThumbPath(){ return $this->thumbnail_path; } function setCreateThumbnail($create){ $this->create_thumb = $create; } function setMaxFileSize($size){ $this->max_filesize = $size; } function setAllowFileType($type_array){ $this->allow_type = $type_array; } function setThumbDimension($width, $height){ $this->thumb_width = $width; $this->thumb_height = $height; } function isUploadError(){ return $this->upload_err; } function getUploadMsg(){ return $this->upload_err_msg; } function setPicName($name){ $this->set_name = $name; } function setThumbMode($mode){ $mode = strtolower($mode); if($mode == "exact" || $mode == "stretch" || $mode == "crop") $this->thumb_mode = $mode; }

The function below is showing you the way to upload picture

    function uploadImg($fieldname = ''){
        //check if another fieldname is specified, or get fieldname that is assigned on initialization
        if($fieldname == "") $fieldname = $this->fieldname;

        //get upload info
        $pic_name = $_FILES[$fieldname]['name'];
        $pic_type = $_FILES[$fieldname]['type'];
        $pic_size = $_FILES[$fieldname]['size'];
        $pic_tmp = $_FILES[$fieldname]['tmp_name'];
        $pic_err = $_FILES[$fieldname]['error'];
    
        //check if file is uploaded, file size must exists
        if($pic_size > 0){
            //check valid filesize
            if($pic_size > $this->max_filesize && $this->max_filesize != 0){
                $this->upload_err = 1;
                $this->upload_err_msg[] = "File too large, limit size $max_filesize byte.";
                return false;
            }
            
            //check if file type is allowed
            if(!isset($this->allow_type[$pic_type])){
                $this->upload_err = 1;
                $this->upload_err_msg[] = "File type not allow";
                return false;
            }
    
            //save uploaded image
            $fulldir = $this->upload_path;
            
            //check and set folder permission
            if(!is_dir($fulldir)) mkdir($fulldir, 0755);
            if(!is_writable($fulldir)) chmod($fulldir, 0755);
        
            //check and set picture file name
            if($this->set_name){
                $pic_name = $this->set_name.".".substr(strrchr($pic_name, "."), 1);
            }else{
                //you may want to append date/time to file name
                $filename = substr($pic_name, 0, strrpos($pic_name, "."));
                $ext = substr(strrchr($pic_name, '.'), 1);
                
                $pic_name = $filename."-".date('YmdHis').".$ext";
            }
            
            //save full image
            if(!move_uploaded_file($pic_tmp, $fulldir . $pic_name)) {
                $this->upload_err_msg[] = "File upload fail, could not copy the upload file";
                return false;
            }
        
            //if create_thumb is assigned to true
            if($this->create_thumb){
                //call function to build thumbnail
                $this->buildThumbnail($pic_name);
            }
            
            //return picture name for another usage
            return $pic_name;
        }else{
            $this->upload_err = 1;
            $this->upload_err_msg[] = "File size is zero";

            return false;
        }
    }

The function below is about to build the thumbnail from source file specified

    function buildThumbnail($file_name, $thumb_name = ""){
        //set source path
        $fulldir = $this->upload_path;        
        $full_path_img = $fulldir . $file_name;
        
        //set thumbnail path
        $thumbdir = $this->thumbnail_path;
        
        //check if another thumbnail name specified, or use the same name as source file
        if($thumb_name)
            $thumb_path_img = $thumbdir . $thumb_name;
        else
            $thumb_path_img = $thumbdir . $file_name;
        
        //validate source path
        if(is_file($full_path_img)){		
            $image_attribs = getimagesize($full_path_img);
            
            if(!is_dir($thumbdir)) mkdir($thumbdir, 0755);
            if(!is_writable($thumbdir)) chmod($thumbdir, 0755);
            
            //get thumbnail size
            $th_max_width = $this->thumb_width;
            $th_max_height = $this->thumb_height;
            
            //get file mime type, you can try another way if server support the method ;)
            $ext = strtolower(substr(strrchr($full_path_img, '.'), 1));
            switch($ext){
                case "png": $file_mime_type = "image/png"; break;
                case "gif": $file_mime_type = "image/gif"; break;
                case "jpg": 
                case "jpeg": 
                default:
                    $file_mime_type = "image/jpeg"; break;
                case "wbmp": $file_mime_type = "image/wbmp"; break;
                default: $file_mime_type = "others";
            }
            
            //find ratio of full picture compare to thumbnail
            $ratio_h = ceil(($image_attribs[1]*$th_max_width)/$image_attribs[0]);
            $ratio_w = ceil(($image_attribs[0]*$th_max_height)/$image_attribs[1]);
            
            //create source image
            if (!strcmp($file_mime_type, "image/gif")) {
               $im_old = imagecreatefromgif($full_path_img); 
            } elseif (!strcmp($file_mime_type, "image/pjpeg") || !strcmp($file_mime_type, "image/jpeg")) {
                $im_old = imagecreatefromjpeg($full_path_img); 
            } elseif (!strcmp($file_mime_type, "image/png") || !strcmp($file_mime_type, "image/x-png")) {
               $im_old = imagecreatefrompng($full_path_img); 
            } elseif (!strcmp($file_mime_type, "image/wbmp")) {
               $im_old = imagecreatefromwbmp($full_path_img); 
            } else {
               //die("Image not support");
               $this->upload_err = 1;
               $this->upload_err_msg[] = "Image not support";
            }
            
            switch($this->thumb_mode){
                case "stretch":
                    //proceed stretch mode
$th_width = $th_max_width;
$th_height = $th_max_height; $im_new = imagecreatetruecolor($th_width,$th_height); // preserve transparency if($file_mime_type == "image/gif" || $file_mime_type == "image/png"){ imagecolortransparent($im_new, imagecolorallocatealpha($im_new, 0, 0, 0, 127)); imagealphablending($im_new, false); imagesavealpha($im_new, true); } imageCopyResampled($im_new,$im_old,0,0,0,0,$th_width,$th_height, $image_attribs[0], $image_attribs[1]); break; case "crop": //proceed crop mode, thumbnail will be calculated at source image center if($ratio_w<$th_max_width){
//based on width
$ratio = $th_max_width/$image_attribs[0];
}else{
//based on height
$ratio = $th_max_height/$image_attribs[1];
}

$th_width = $image_attribs[0] * $ratio;
$th_height = $image_attribs[1] * $ratio; $im_temp = imagecreatetruecolor($th_width,$th_height); // preserve transparency if($file_mime_type == "image/gif" || $file_mime_type == "image/png"){ imagecolortransparent($im_temp, imagecolorallocatealpha($im_temp, 0, 0, 0, 127)); imagealphablending($im_temp, false); imagesavealpha($im_temp, true); } imageCopyResampled($im_temp,$im_old,0,0,0,0,$th_width,$th_height, $image_attribs[0], $image_attribs[1]); $x0 = ( $th_width - $th_max_width ) / 2; $y0 = ( $th_height - $th_max_height ) / 2; $im_new = imagecreatetruecolor( $th_max_width, $th_max_height ); // preserve transparency if($file_mime_type == "image/gif" || $file_mime_type == "image/png"){ imagecolortransparent($im_new, imagecolorallocatealpha($im_new, 0, 0, 0, 127)); imagealphablending($im_new, false); imagesavealpha($im_new, true); } imagecopy($im_new, $im_temp, 0, 0, $x0, $y0, $th_max_width, $th_max_height); break; default: //proceed exact mode if($ratio_w<$th_max_width){ //based on height $ratio = $th_max_height/$image_attribs[1]; }else{ //based on width $ratio = $th_max_width/$image_attribs[0]; } $th_width = $image_attribs[0] * $ratio; $th_height = $image_attribs[1] * $ratio; $im_new = imagecreatetruecolor($th_width,$th_height); // preserve transparency if($file_mime_type == "image/gif" || $file_mime_type == "image/png"){ imagecolortransparent($im_new, imagecolorallocatealpha($im_new, 0, 0, 0, 127)); imagealphablending($im_new, false); imagesavealpha($im_new, true); } imageCopyResampled($im_new,$im_old,0,0,0,0,$th_width,$th_height, $image_attribs[0], $image_attribs[1]); break; } //output thumbnail if (!strcmp($file_mime_type, "image/gif") && function_exists("imagegif")) { imagegif($im_new,$thumb_path_img); } elseif (!strcmp($file_mime_type, "image/pjpeg") || !strcmp($file_mime_type, "image/jpeg")
&& function_exists("imagejpeg")) { imagejpeg($im_new,$thumb_path_img,100); } elseif ((!strcmp($file_mime_type, "image/png") || !strcmp($file_mime_type, "image/x-png"))
&& function_exists("imagepng")) { imagepng($im_new,$thumb_path_img); } elseif (!strcmp($file_mime_type, "image/wbmp") && function_exists("imagewbmp")) { imagewbmp($im_new,$thumb_path_img); }elseif(function_exists("imagejpeg")){ imagejpeg($im_new,$thumb_path_img,100); } } } } //end of class ?>

Example result thumbnails on each mode

Source (1920x1080)
Exact (100x56)
Stretch (100x100)
Crop (100x100)

 

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