Image upload, tjek type først.

Et hurtig bud (Ikke testet):

 <?php
 $uploadDir = "billeder/";
 $acceptedFormats = array('gif', 'png', 'jpg');
 
  foreach ($_FILES['userImage']['name'] as $name => $value){
     if(in_array(pathinfo($_FILES['userImage']['tmp_name'][$name], PATHINFO_EXTENSION), $acceptedFormats)) {
         if(is_uploaded_file($_FILES['userImage']['tmp_name'][$name])) {
  
         $id = md5(time());
         $dato = date("d/m-y");
         $time = date("H:i");
         $sourcePath = $_FILES['userImage']['tmp_name'][$name];
         $targetPath = $id.$_FILES['userImage']['name'][$name];
         
         mysql_query("INSERT INTO `hansen_billeder` (file, dato) VALUES ('".$targetPath."','".$dato." kl. ".$time."')");
         
             if(move_uploaded_file($sourcePath, $uploadDir . $targetPath)) {
  ?>
  <img src="/admin/sider/billeder/<?php echo $targetPath; ?>" title="<?php echo $dato; ?> kl. <?php echo $time; ?>" width="150px" height="180px" />
                  <script>
                  ajaxupload();
                  </script>
  <?php
     }else{
         echo $_FILES['userImage']['tmp_name'][$name]." kunne ikke uploades da typen ikke er godkendt";
     }
         }
             }else{
             echo "Fejl";
             }
  }
 ?>

Evt. brug getimagesize() som nok er lidt mere præcis end at tjekke en fil endelse. :o)
http://php.net/manual/en/function.getimagesize.php

http://stackoverflow.com/questions/1495852/check-upload-file-type-from-an-array-in-php

 // $upload_permitted_types er dit array
 if (!in_array($_FILES['post_name_here']['type'], $upload_permitted_types)){
 
    exit("Unsupported file type");
 }

Ikke testet, men blot en simpel Google-søgning.

Løsning fundet hen over TW.

Løsning:

 <?php
 $uploadDir = "billeder/";
 $acceptedFormats = array('gif', 'png', 'jpg');
 foreach ($_FILES['userImage']['name'] as $name => $value){
 $path_parts =  pathinfo($_FILES['userImage']['name'][$name]);
 
 if(in_array($path_parts['extension'], $acceptedFormats)) {
 
 if(is_uploaded_file($_FILES['userImage']['tmp_name'][$name])) {
 
 $id = md5(time());
 $dato = date("d/m-y");
 $time = date("H:i");
 $sourcePath = $_FILES['userImage']['tmp_name'][$name];
 $targetPath = $id.$_FILES['userImage']['name'][$name];
 mysql_query("INSERT INTO `hansen_billeder` (file, dato) VALUES ('".$targetPath."','".$dato." kl. ".$time."')");
 if(move_uploaded_file($sourcePath, $uploadDir . $targetPath)) {
 ?>
                 <script>
                 ajaxupload();
                 </script>
 <img src="/admin/sider/billeder/<?php echo $targetPath; ?>" title="<?php echo $dato; ?> kl. <?php echo $time; ?>" width="150px" height="180px" />
 <?php
 }else{
 echo "Fejl";
 }
 }
 }else{
 echo $_FILES['userImage']['tmp_name'][$name]." kunne ikke uploades da typen ikke er godkendt";
 }
 }
 ?>

Udlempen er at den spammer med
<script>
ajaxupload();
</script>

Eller med teksten echo "uploaded";

Hvis flere end 1 billede.

Den skulle helst kun udskrive sætning 1 gang, ligegyldig antal billeder valgt til uploading ..