Resizing give some black image

Question

I'm using a function to resize pictures.

Most of images are resized very well. but someone, I don't why are only black. the same picture always give black result. May be it's the kind of Jpeg who give this.. but how to change it?

Thanks !

function create_image($file) {
    if(is_file($file)) {
        $size = getimagesize($file);
        // y =hauteur en pixel
        $y = 800;
        $x = $size[0]/$size[1]*$y;
        //$y = 75; # Taille en pixel de l'image redimensionnée
        if ($size) {
            if ($size['mime']=='image/jpeg' ) {
                $img_big = imagecreatefromjpeg($file);
                $img_new = imagecreate($x, $y);
                # création de la miniature
                $img_mini = imagecreatetruecolor($x, $y)
                or   $img_mini = imagecreate($x, $y);

                // copie de l'image, avec le redimensionnement.
                imagecopyresized($img_mini,$img_big,0,0,0,0,$x,$y,$size[0],$size[1]);

                imagejpeg($img_mini,$file );

            }
            elseif ($size['mime']=='image/png' ) {
                $img_big = imagecreatefrompng($file);
                $img_new = imagecreate($x, $y);
                # création de la miniature
                $img_mini = imagecreatetruecolor($x, $y)
                or   $img_mini = imagecreate($x, $y);

                // copie de l'image, avec le redimensionnement.
                imagecopyresized($img_mini,$img_big,0,0,0,0,$x,$y,$size[0],$size[1]);

                imagepng($img_mini,$file );

            }
            elseif ($size['mime']=='image/gif' ) {
                $img_big = imagecreatefromgif($file);
                $img_new = imagecreate($x, $y);
                # création de la miniature
                $img_mini = imagecreatetruecolor($x, $y)
                or   $img_mini = imagecreate($x, $y);

                // copie de l'image, avec le redimensionnement.
                imagecopyresized($img_mini,$img_big,0,0,0,0,$x,$y,$size[0],$size[1]);

                imagegif($img_mini,$file ); 
            }
            // move_uploaded_file($img_mini,$dir."test");
        }
        return true;
    } else {
        return false;
    }
}

EDIT : Thanks !

The optimisation is good ...

But the result is the same with the images like : http://www.ericae.fr/test_images/Ripper.jpg resized give : http://www.ericae.fr/test_images/resized.jpg All black :(

With others images the result is good !!! I've test around 25 images only 2 makes problems... WHY ????

score 0 · Accepted Answer · answered Nov 01 '13 at 08:13

I decided to review your code. Why do you use the same procedures many times when you can do it once? Also I recommend to use imagecopyresampled instead of imagecopyresized, it will give you a better result without black screens. Look at this, I commented anything that I changed for you:

function create_image($file)
{
    if(is_file($file))
    {
        $size = getimagesize($file);

        if ($size)
        {
            $y = 800;
            $x = $size[0]/$size[1]*$y;
            $mime = $size['mime'];

            // Detect image format and create a GD resource 
            switch ($mime)
            {
                case 'image/jpeg' : $img_big = imagecreatefromjpeg($file); break;
                case 'image/png' : $img_big = imagecreatefrompng($file); break;
                case 'image/gif' : $img_big = imagecreatefromgif($file); break;
                // Wrong type - exiting
                default: return false;
            }

            // Create a new image for resizing
            $img_mini = imagecreatetruecolor($x, $y);

            // This function is better for image resizing than imagecopyresized
            // Gives you better quality and no black screens
            imagecopyresampled($img_mini,$img_big,0,0,0,0,$x,$y,$size[0],$size[1]);

            // OK, now we ready to save your image!
            // We will save it in the same format as original
            switch ($mime)
            {
                case 'image/jpeg' : $img_big = imagejpeg($img_mini, $file); break;
                case 'image/png' : $img_big = imagepng($img_mini, $file); break;
                case 'image/gif' : $img_big = imagegif($img_mini, $file); break;
                default: return false;
            }

            // Don't forget to free memory.
            imagedestroy($img_big); imagedestroy($img_mini);

            return true;

            //  Don't do this. It's wrong.
            //  move_uploaded_file($img_mini,$dir."test");
        }   
        // didn't get size
        else
            return false;
    } // isn't a file
    else 
        return false;
}

I hope it was useful for you :3

Thanks a lot for optimisation ! but it's the same for "black image" — Florent Pichon, Nov 01 '13 at 09:02
@FlorentPichon Maybe these images are corrupted? Or your GD doesn't support them? Try create a new resource with these images and just save them as JPEG, for example: `$img = imagecreatefromjpeg('Ripper.jpg'); imagejpeg($img, './test.jpg');`. Will it get a black screen? If yes, your GD doesn't support this image. If not — try to check `$size` array, did PHP get right data from the image? — namikiri, Nov 01 '13 at 10:07
I've tested this code on my server and it worked fine with your image: http://test.nyanserver.com/ripper/Ripper.jpg So, I think you have to look at your GD bundle. — namikiri, Nov 01 '13 at 10:22

score 0 · Answer 2 · answered Nov 01 '13 at 08:56

use this file to re size the images

one thing to note - it may not support gif. Enable GD library.

usage

<img src="resizeImage.php?w=x&h=z&img=path/to/image" border="0'>

This is the image resize file: resizeImage.php

    <?php
header ("Content-type: image/jpeg");
/*
JPEG / PNG Image Resizer
Parameters (passed via URL):

img = path / url of jpeg or png image file

percent = if this is defined, image is resized by it's
          value in percent (i.e. 50 to divide by 50 percent)

w = image width

h = image height

constrain = if this is parameter is passed and w and h are set
            to a size value then the size of the resulting image
            is constrained by whichever dimension is smaller

Requires the PHP GD Extension

Outputs the resulting image in JPEG Format

*/

$img = $_GET['img'];
$percent = $_GET['percent'];
$constrain = $_GET['constrain'];
$w = $_GET['w'];
$h = $_GET['h'];

// get image size of img
$x = @getimagesize($img);
// image width
$sw = $x[0];
// image height
$sh = $x[1];

if ($percent > 0) {
    // calculate resized height and width if percent is defined
    $percent = $percent * 0.01;
    $w = $sw * $percent;
    $h = $sh * $percent;
} else {
    if (isset ($w) AND !isset ($h)) {
        // autocompute height if only width is set
        $h = (100 / ($sw / $w)) * .01;
        $h = @round ($sh * $h);
    } elseif (isset ($h) AND !isset ($w)) {
        // autocompute width if only height is set
        $w = (100 / ($sh / $h)) * .01;
        $w = @round ($sw * $w);
    } elseif (isset ($h) AND isset ($w) AND isset ($constrain)) {
        // get the smaller resulting image dimension if both height
        // and width are set and $constrain is also set
        $hx = (100 / ($sw / $w)) * .01;
        $hx = @round ($sh * $hx);

        $wx = (100 / ($sh / $h)) * .01;
        $wx = @round ($sw * $wx);

        if ($hx < $h) {
            $h = (100 / ($sw / $w)) * .01;
            $h = @round ($sh * $h);
        } else {
            $w = (100 / ($sh / $h)) * .01;
            $w = @round ($sw * $w);
        }
    }
}

$im = @ImageCreateFromJPEG ($img) or // Read JPEG Image
$im = @ImageCreateFromPNG ($img) or // or PNG Image
$im = @ImageCreateFromGIF ($img) or // or GIF Image
$im = false; // If image is not JPEG, PNG, or GIF

if (!$im) {
    // We get errors from PHP's ImageCreate functions...
    // So let's echo back the contents of the actual image.
    readfile ($img);
} else {
    // Create the resized image destination
    $thumb = @ImageCreateTrueColor ($w, $h);
    // Copy from image source, resize it, and paste to image destination
    @ImageCopyResampled ($thumb, $im, 0, 0, 0, 0, $w, $h, $sw, $sh);
    // Output resized image
    @ImageJPEG ($thumb);
}
?>

Resizing give some black image

2 Answers2