How to create a thumbnail image using PHP

[Tony]

Creating thumbnail images is a very common requirement. Many scripts use this to create thumbnails of uploaded images or any stored images. We will learn how to create thumbnail images while uploading images to the server.

The file ( or image ) will be first uploaded to a directory and then one thumbnail image will be created in a different directory. So for creating and the thumbnail we will check the file extension ( it is gif or jpeg image ) but to keep the script simple we are not checking here the file size. So if the file size is to be restricted then that validation is to be added. You can see how the file size checking is done in file upload tutorial.

The file ( or image ) will be first uploaded to a directory and then one thumbnail image will be created in a different directory. So for creating the thumbnail we will check the file extension ( it is gif or jpeg image ) but to keep the script simple we are not checking here the file size. So if the file size is to be restricted then file size validation is to be added. You can see how the file size checking is done in file upload tutorial.

This script is tested with PHP 5.2.6 with register_global is OFF. Please update your script if you have downloaded the old version of this.

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<form enctype="multipart/form-data" action="addimgck.php" method=post>
Upload this file: <input name="userfile" type="file">
<input type="submit" value="Send File"></form>
 

We will now see the addimgck.php file and check the code to create the thumbnail image. We will upload the file to the upimg directory and check to see if file upload is successful or not.

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// Below lines are to display file name, temp name and file type , you can use them for testing your script only//////
echo "File Name: ".$_FILES[userfile][name]."<br>";
echo "tmp name: ".$_FILES[userfile][tmp_name]."<br>";
echo "File Type: ".$_FILES[userfile][type]."<br>";
echo "<br><br>";
///////////////////////////////////////////////////////////////////////////
$add="upimg/".$_FILES[userfile][name]; // the path with the file name where the file will be stored, upload is the directory name. 
//echo $add;
if(move_uploaded_file ($_FILES[userfile][tmp_name],$add)){
echo "Successfully uploaded the mage";
chmod("$add",0777);

}else{echo "Failed to upload file Contact Site admin to fix the problem";
exit;}
 

Now the image is uploaded to the directory and from that image we will create thumbnail image of it. We will first set the height and width of the thumbnail images to be generated. Then we will check the type of the file and now we are checking for file type of gif and jpeg and if the image is not of this type then we are terminating the script giving an error message.

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///////// Start the thumbnail generation//////////////
$n_width=100; // Fix the width of the thumb nail images
$n_height=100; // Fix the height of the thumb nail imaage

$tsrc="thimg/".$_FILES[userfile][name]; // Path where thumb nail image will be stored
//echo $tsrc;
if (!($_FILES[userfile][type] =="image/pjpeg" OR $_FILES[userfile][type]=="image/gif")){echo "Your uploaded file must be of JPG or GIF. Other file types are not allowed<BR>";
exit;} 

Now let us start with gif file thumb nail image creation. We will first read the height and width of the uploaded image and then resize it to our thumbnail image size. Note that in some GD library support GIF version is not included so to check that we have used one if condition and accordingly used jpeg support. We will be using imagecreatetruecolor to retain the actual color combination of the main picture.

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//////////// Starting of GIF thumb nail creation///////////
if (@$_FILES[userfile][type]=="image/gif")
{
$im=ImageCreateFromGIF($add);
$width=ImageSx($im); // Original picture width is stored
$height=ImageSy($im); // Original picture height is stored
$newimage=imagecreatetruecolor($n_width,$n_height);
imageCopyResized($newimage,$im,0,0,0,0,$n_width,$n_height,$width,$height);
if (function_exists("imagegif")) {
Header("Content-type: image/gif");
ImageGIF($newimage,$tsrc);
}
elseif (function_exists("imagejpeg")) {
Header("Content-type: image/jpeg");
ImageJPEG($newimage,$tsrc);
}
chmod("$tsrc",0777);
}////////// end of gif file thumb nail creation//////////

////////////// starting of JPG thumb nail creation//////////
if($_FILES[userfile][type]=="image/pjpeg"){
$im=ImageCreateFromJPEG($add); 
$width=ImageSx($im); // Original picture width is stored
$height=ImageSy($im); // Original picture height is stored
$newimage=imagecreatetruecolor($n_width,$n_height); 
imageCopyResized($newimage,$im,0,0,0,0,$n_width,$n_height,$width,$height);
ImageJpeg($newimage,$tsrc);
chmod("$tsrc",0777);
}
//////////////// End of JPG thumb nail creation //////////