Uploading Problem Help Please

[khan]

Hello Friends,
I got a prob in my site.when i give uploader to upload pic to user,they can easily upload shell in their.
actually i did it in my own site.i think its an major problem, as because any one can easily hack my site. hackers now convert the shell into gif or jpg format and then upload it. how can i stop these kinda execution.
how can i secure my uploader.i used accept only gif and jpeg .htaccess. but its not working.
Help Me please.

[albertynos]

don't give uploader...

[khan]

noobs should not reply this

[djlee]

/*** $filename = the filename of the uploaded image ***
 *** $file = the actual uploaded image file ***/

//=== Check name extension
$allow = array("gif","jpg","jpeg","png","bmp");
$ext = substr(strpos($filename, ".")+1);
if(!in_array($ext,$allow))
 die("not allowed");

//=== check mimetype
$allowmime = array("image/jpeg","image/gif","image/png");
if(function_exists("mime_content_type"))
 $mime = mime_content_type($file);
else {
 $imgres = getimagesize($file);
 $mime = image_type_to_mime_type($imgres[2]);
}
if(!$mime || !in_array($mime,$allowmime))
 die("not allowed again");

[metulj]

noobs should not reply this

and noobs are...?
i mean.. who the F... are you to judge who can and who cannot reply?
you got question.. post it and wait... and dont judge ppl by their replies
sometimes so called noob can post simple yet effective solution...
on the other hand.. even pro's make mistakes...
and noob will never learn.. if he doesnt post his idea eventhough they might be wrongly coded...
but usually after... some pro can/will fix posted code for his idea...