Automatic file size reduction

[deb0and]

Hi

I have a web site that allows users to upload pictures but i only allow them a maximum of 500kb per picture. What would be nice if it can be done is that when they upload there pictures it will automatically reduce the file size to 500kb, can this be done? This would then save my advertisers time and inconvineience hence i might get more people advertising.

TY

[Rakuli]

The best way to do this would be to resize the image to a predetermined max height/width. You would be able to do this with the PHP GD module.

[deb0and]

Thanks, any resources you can point me to to achieve this. Or a working example wouild be great.

[Rakuli]

Okay here's a quick example using a file found in $_FILES['pic']..

The error handling is tack as it's only an example

PHP: Select all

$allowed = array('jpg', 'jpeg', 'gif', 'png');



$picH = '500'; // maxium height

$picW = '500'; // maximum width

// first we'll check this is a valid file and go from there



if (!is_uploaded_file($_FILES['pic']['tmp_name']))

   die ('You\'re naughty! Don\'t try hack me!');



// okay so its a valid file let's get the extension



$ext = explode('.', $_FILES['pic']['name']);

$ext = strtolower($ext[count($ext)-1]);



//check if file type is okay...

if (!in_array($ext, $allowed))

    die ('That file type is not allowed');



$ext = $ext == 'jpg' ? 'jpeg' : $ext; // need to turn jpg to jpeg for later.



// let's get the uploaded images dimensions



$dim = getimagesize($_FILES['pic']['tmp_name']); // gets an array of image dimenstions [0]= width [1] = height



// work by what percentage we would have to resize to for each



$ph = ceil(($picH / $dim[1]) * 100);

$pw = ceil(($picW / $dim[0]) * 100);



// okay, now, if the either dimension is greater than 100% of the allowed we need to recalculate



if ($ph > 100 || $pw > 100)

   $rc = $pc = $pw > $ph ? $pw / 100 : $ph / 100; // take the largest percentage decrease



$width = ceil($dim[0] * $rc); // new width

$height = ceil($dim[1] * $rc); // new height



// get rid of our working variables

unset($ph, $pw);



// get the binary data from the old image

$func = 'imagecreatefrom' . $ext

$om = $func($_FILES['pic']['tmp_name']);



// create the new image





$im = imagecreatetruecolor($width, $height);



// now resample the old image into the new one based on our new width and height



$im = imagecopyresampled($im, $ol, 0,0,0,0, $width, $height, $dim[0], $dim[1]);



// now we'll store it ... as a jpg (but you can just replace imagejpg with image $ext



imagejpeg($im, 'C:/Path/to/where/you/want/' . $_FILES['pic']['name']);

} 

I don't work with images too often but that's a quick look at how I would do it... I went pretty quickly so the maths is a bit chunky

[deb0and]

wow thanks thats a great example, wasnt expecting anything that good I will work on that and get it to work with my current site.
Thanks again