How do I auto resize user's inputted images to a specific dimension in PHP?

Question

When users input their images, their images are any size. I want to be able to resize all the images to a specific dimension. Is there a function that allows me to do that i

Answer 1

The function you need is imagecopyresampled, that also interpolate pixels, (imagecopyresized does not);
In my code I use a it in a function like this:

function resizeAndSavePhoto($original, $destination, $dest_width, $dest_height){    
    $photo = createImage($original);
    $size =  getimagesize($original);

    $final_photo = imagecreatetruecolor($dest_width, $dest_height);

    imagecopyresampled($final_photo, $photo,0,0,0,0,$dest_width, $dest_height, $size[0], $size[1]);
    imagejpeg($final_photo, $destination, 100);
}

$orignal and $destination are filename paths