php and image size / resize

variable

using this function

//resize image if necessary
function resizeimg($img){
if($img){
list($width, $height, $type, $attr) = getimagesize($img);
echo "<img src=\"" . $img . "\" width=\"";
if ($width>450) {
echo "450";
} else {
echo $width;
}

echo "\">";
}

}

my site seems to lock up every time that i submit a .png to it. anyone have this problem with getimagesize()?

Installer

Look in phpinfo and see if png support is enabled (under gd).

variable

it is, i did not know i had gd, until i just now checked, to my knowledge getimagesize is not a gd function. however i would now like to use gd if possible.

Installer

You're right; I'd forgotten that, since it's documented along with the gd functions. As to why "getimagesize(*.png)" would lock up a server, I'm afraid I don't know. Do you have error reporting and error display turned on?

variable

how would i go about doing that?

Installer

You can do it in php.ini, .htaccess, or per script. To do it per script, add this to the top of your script:

ini_set('error_reporting', E_ALL);
ini_set('display_errors', 1);

There's more information and options here.

variable

it must just be that it takes soooo long. i put in a tiny .png and it worked(but took 1.5 minutes). i need something faster!

variable

if i use gd, what is the quickest way to do this?

Installer

Look at the user's note dated 02-Feb-2002 here. That code should get you started pretty well. Just pull the code out of the function and put it in a separate file, then call that file from your image tag. Change the jpeg-specific parts to png ("imagecreatefrompng", "imagepng", etc.) and use only the first parameter in the "imagepng()" argument. Oh, and put a "header('Content-Type: image/png');" line in there.

Installer

Like this:

$src_image = 'path/to/image.png';
$picsize = getimagesize($src_image);
$source_x = $picsize[0];
$source_y = $picsize[1];
$dest_x = ceil($source_x / 2);
$dest_y = ceil($source_y / 2);
$source_id = imagecreatefrompng($src_image);
$target_id = imagecreatetruecolor($dest_x, $dest_y);
$target_pic = imagecopyresampled($target_id, $source_id,
                                 0, 0, 0, 0,
                                 $dest_x, $dest_y,
                                 $source_x, $source_y);
header('Content-Type: image/png');
imagepng ($target_id);

That will resize an image to half-size. Whatever size you want, just substitute for the "$dest_" values.

variable

would this be alot quicker than getimagesize ??

Installer

Try it and see.

The way you're doing it doesn't acturally "resize" the picture (all "getimagesize()" does is retrieve information apout an image), it just squeezes it into a smaller box. If it takes 1.5 minutes to load, I'd say you have server troubles of a different sort.