freaCMS/app/modules/cachedimage.php

<?php

namespace Modules;

class CachedImage {

    public $original;
    public $cache_dir = "rsc/img_display/";
    public $default_width = 500;

    function __construct($path) {
        $this->original = $path;
    }
    
    function get_src($inwidth = 500) {
        $f3 = \Base::instance();
        if($this->is_image($this->original)) {
            $info = pathinfo($this->original);
            $fn = basename($this->original,'.'.$info['extension']);
            $width = $inwidth ? $inwidth : $this->default_width;
            $name = md5($this->original.$width);
        
            $name =  sprintf("%s_%s.jpg",$fn,$name);
        
            $out = $this->cache_dir.$name;
    
            //if(!file_exists($this->original)) { $this->original='rsc/img/default.png'; }
    
            if(!file_exists($out)) {
                $img1 = new \Image($this->original);
                $img1->resize($width);
                $f3->write($out,$img1->dump('jpeg',75));
            }
        } else {
            $out = $this->original;
        }
        return $out;
    }

    function is_image($path) {
        $ex = explode('.',$path);
        $ext = array_pop($ex);
        return in_array(strtolower($ext),array( 'jpg', 'jpeg', 'png' ));
    }
}