Create thumnail to existing image with GD - php

Question

I want to create thumb for existing image. I have three image input fields and only want for 1st image to make thumb.
$_FILES['img_1']['name']
$_FILES['img_2']['name']
$_FILES['img_3']['name']
And for create i usee this function
function createThumbnail($filename, $path_to_image_directory, $final_width_of_image, $path_to_thumbs_directory) {
if(preg_match('/[.](jpg)$/', $filename)) {
$im = imagecreatefromjpeg($path_to_image_directory . $filename);
} else if (preg_match('/[.](gif)$/', $filename)) {
$im = imagecreatefromgif($path_to_image_directory . $filename);
} else if (preg_match('/[.](png)$/', $filename)) {
$im = imagecreatefrompng($path_to_image_directory . $filename);
}else if (preg_match('/[.](jpeg)$/', $filename)) {
$im = imagecreatefrompng($path_to_image_directory . $filename);
}
$ox = imagesx($im);
$oy = imagesy($im);
$nx = $final_width_of_image;
$ny = floor($oy * ($final_width_of_image / $ox));
$nm = imagecreatetruecolor($nx, $ny);
imagecopyresized($nm, $im, 0,0,0,0,$nx,$ny,$ox,$oy);
if(!file_exists($path_to_thumbs_directory)) {
if(!mkdir($path_to_thumbs_directory)) {
die("There was a problem. Please try again!");
}
}
imagejpeg($nm, $path_to_thumbs_directory . $filename);
$tn = '<img src="' . $path_to_thumbs_directory . $filename . '" alt="image" />';
$tn .= '<br />Congratulations. Your file has been successfully uploaded, and a thumbnail has been created.';
echo $tn;
}
And when i call createThumbnail($_FILES["img_1"]["tmp_name"],'./uploads', 370, './uploads');
Files are successfull moved to directory img_1, img_2, img_3 but thumb is not created. I set error to E_ALL to see and i get to many warrnings.
Notice: Undefined variable: im in
/var/www/http_myoffice/petbook/web/ogi/admin/dodaj_vozilo_proccess.php
on line 21
Warning: imagesx() expects parameter 1 to be resource, null given in
/var/www/http_myoffice/petbook/web/ogi/admin/dodaj_vozilo_proccess.php
on line 21
Notice: Undefined variable: im in
/var/www/http_myoffice/petbook/web/ogi/admin/dodaj_vozilo_proccess.php
on line 22
Warning: imagesy() expects parameter 1 to be resource, null given in
/var/www
Warning: Division by zero in /var/www/
Warning: imagecreatetruecolor(): Invalid image dimensions in /var/www
Notice: Undefined variable: im in /var/www/
Warning: imagecopyresized() expects parameter 1 to be resource,
boolean given in /var/www/
Warning: imagejpeg() expects parameter 1 to be resource, boolean given
in /var/www/ image Congratulations. Your file has been successfully
uploaded, and a thumbnail has been created.

Answer 1

Your problem seems to be that you pass the temp name of the image to the function. This temp name has no file extension. You have to pass the name (with extension) and the temp name (path to file on disk).
If you want to get rid of the regex search for the file type, a user could upload a file with wrong extension, you can use $image = imagecreatefromstring( file_get_contents( $path ) );. PHP GD will get the file type on its own.
Changed PHP Code:
function createThumbnail($tempname, $filename, $final_width_of_image, $path_to_thumbs_directory) {
$im = imagecreatefromstring( file_get_contents( $tempname ) );
$ox = imagesx($im);
$oy = imagesy($im);
$nx = $final_width_of_image;
$ny = floor($oy * ($final_width_of_image / $ox));
$nm = imagecreatetruecolor($nx, $ny);
imagecopyresized($nm, $im, 0,0,0,0,$nx,$ny,$ox,$oy);
if(!file_exists($path_to_thumbs_directory)) {
if(!mkdir($path_to_thumbs_directory)) {
die("There was a problem. Please try again!");
}
}
imagejpeg($nm, $path_to_thumbs_directory . $filename . '.jpg');
$tn = '<img src="' . $path_to_thumbs_directory . $filename . '" alt="image" />';
$tn .= '<br />Congratulations. Your file has been successfully uploaded, and a thumbnail has been created.';
echo $tn;
}
Edit:
You can call this function:
createThumbnail($_FILES["img_1"]["tmp_name"],$_FILES["img_1"]["name"], 370, './uploads');