Creating a thumbnail from an uploaded image

UPDATE:

If you want to take advantage of Imagick (if it is installed on your server). Note: I didn't use Imagick's nature writeFile because I was having issues with it on my server. File put contents works just as well.

<?php
/**
 * 
 * Generate Thumbnail using Imagick class
 *  
 * @param string $img
 * @param string $width
 * @param string $height
 * @param int $quality
 * @return boolean on true
 * @throws Exception
 * @throws ImagickException
 */
function generateThumbnail($img, $width, $height, $quality = 90)
{
    if (is_file($img)) {
        $imagick = new Imagick(realpath($img));
        $imagick->setImageFormat('jpeg');
        $imagick->setImageCompression(Imagick::COMPRESSION_JPEG);
        $imagick->setImageCompressionQuality($quality);
        $imagick->thumbnailImage($width, $height, false, false);
        $filename_no_ext = reset(explode('.', $img));
        if (file_put_contents($filename_no_ext . '_thumb' . '.jpg', $imagick) === false) {
            throw new Exception("Could not put contents.");
        }
        return true;
    }
    else {
        throw new Exception("No valid image provided with {$img}.");
    }
}

// example usage
try {
    generateThumbnail('test.jpg', 100, 50, 65);
}
catch (ImagickException $e) {
    echo $e->getMessage();
}
catch (Exception $e) {
    echo $e->getMessage();
}
?>

I have been using this, just execute the function after you store the original image and use that location to create the thumbnail. Edit it to your liking...

function makeThumbnails($updir, $img, $id)
{
    $thumbnail_width = 134;
    $thumbnail_height = 189;
    $thumb_beforeword = "thumb";
    $arr_image_details = getimagesize("$updir" . $id . '_' . "$img"); // pass id to thumb name
    $original_width = $arr_image_details[0];
    $original_height = $arr_image_details[1];
    if ($original_width > $original_height) {
        $new_width = $thumbnail_width;
        $new_height = intval($original_height * $new_width / $original_width);
    } else {
        $new_height = $thumbnail_height;
        $new_width = intval($original_width * $new_height / $original_height);
    }
    $dest_x = intval(($thumbnail_width - $new_width) / 2);
    $dest_y = intval(($thumbnail_height - $new_height) / 2);
    if ($arr_image_details[2] == IMAGETYPE_GIF) {
        $imgt = "ImageGIF";
        $imgcreatefrom = "ImageCreateFromGIF";
    }
    if ($arr_image_details[2] == IMAGETYPE_JPEG) {
        $imgt = "ImageJPEG";
        $imgcreatefrom = "ImageCreateFromJPEG";
    }
    if ($arr_image_details[2] == IMAGETYPE_PNG) {
        $imgt = "ImagePNG";
        $imgcreatefrom = "ImageCreateFromPNG";
    }
    if ($imgt) {
        $old_image = $imgcreatefrom("$updir" . $id . '_' . "$img");
        $new_image = imagecreatetruecolor($thumbnail_width, $thumbnail_height);
        imagecopyresized($new_image, $old_image, $dest_x, $dest_y, 0, 0, $new_width, $new_height, $original_width, $original_height);
        $imgt($new_image, "$updir" . $id . '_' . "$thumb_beforeword" . "$img");
    }
}

The above function creates images with a uniform thumbnail size. If the image doesn't have the same dimensions as the specified thumbnail size (proportionally), it just has blackspace on the top and bottom.


You Can Use The Simplest Method

<?php
function make_thumb($src, $dest, $desired_width) {

    /* read the source image */
    $source_image = imagecreatefromjpeg($src);
    $width = imagesx($source_image);
    $height = imagesy($source_image);

    /* find the "desired height" of this thumbnail, relative to the desired width  */
    $desired_height = floor($height * ($desired_width / $width));

    /* create a new, "virtual" image */
    $virtual_image = imagecreatetruecolor($desired_width, $desired_height);

    /* copy source image at a resized size */
    imagecopyresampled($virtual_image, $source_image, 0, 0, 0, 0, $desired_width, $desired_height, $width, $height);

    /* create the physical thumbnail image to its destination */
    imagejpeg($virtual_image, $dest);
}

$src="1494684586337H.jpg";
$dest="new.jpg";
$desired_width="200";
make_thumb($src, $dest, $desired_width);
?>

I'm guessing you have already figured this one out. But I see that you are storing the images as "longblobs" leading me to think you are storing the entire binary content of the pic.

I hope you have realized that it makes much more sense to simply store the file names in your DB and then use that info to grab the pics out of an "upload" folder or similar.

TIP - dont save a file path.. just the file name .. add the path info in your code as needed. That way you have the most freedom down the line. If you need to change folder structure, you can do it in your code rather than changing DB records.


I know this is an old question, but I stumbled upon the same problem and tried to use the function given in Alex's answer.

But the quality in the jpeg result was too low. So I changed the function a little bit to become more usable in my project and changed the "imagecopyresized" to "imagecopyresampled" (according to this recomendation).

If you are having questions about how to use this function, then try taking a look at the well documented version here.

function createThumbnail($filepath, $thumbpath, $thumbnail_width, $thumbnail_height, $background=false) {
    list($original_width, $original_height, $original_type) = getimagesize($filepath);
    if ($original_width > $original_height) {
        $new_width = $thumbnail_width;
        $new_height = intval($original_height * $new_width / $original_width);
    } else {
        $new_height = $thumbnail_height;
        $new_width = intval($original_width * $new_height / $original_height);
    }
    $dest_x = intval(($thumbnail_width - $new_width) / 2);
    $dest_y = intval(($thumbnail_height - $new_height) / 2);

    if ($original_type === 1) {
        $imgt = "ImageGIF";
        $imgcreatefrom = "ImageCreateFromGIF";
    } else if ($original_type === 2) {
        $imgt = "ImageJPEG";
        $imgcreatefrom = "ImageCreateFromJPEG";
    } else if ($original_type === 3) {
        $imgt = "ImagePNG";
        $imgcreatefrom = "ImageCreateFromPNG";
    } else {
        return false;
    }

    $old_image = $imgcreatefrom($filepath);
    $new_image = imagecreatetruecolor($thumbnail_width, $thumbnail_height); // creates new image, but with a black background

    // figuring out the color for the background
    if(is_array($background) && count($background) === 3) {
      list($red, $green, $blue) = $background;
      $color = imagecolorallocate($new_image, $red, $green, $blue);
      imagefill($new_image, 0, 0, $color);
    // apply transparent background only if is a png image
    } else if($background === 'transparent' && $original_type === 3) {
      imagesavealpha($new_image, TRUE);
      $color = imagecolorallocatealpha($new_image, 0, 0, 0, 127);
      imagefill($new_image, 0, 0, $color);
    }

    imagecopyresampled($new_image, $old_image, $dest_x, $dest_y, 0, 0, $new_width, $new_height, $original_width, $original_height);
    $imgt($new_image, $thumbpath);
    return file_exists($thumbpath);
}