resize the image and overwrite it

[haidoura]

hay guys well i usually read that we can upload and resize it into another size and that is fine but what if i want to add another level like
the picture is 1600x1400 and i want to resize it into 800x600 and overwrite it and after i overwrite it i want to create a new on with the size less than the 800x600 is this possible

can i overwrite a resized image ?????
and can i just resize also this resized image ????????

[onion2k]

You can just resize an image that you've already resized, but every time you do the quality will get lower. If you need to have a few different sized versions of the same image it's much better to generate them all from the original, and then overwrite the original with whatever you want as your final operation.

[haidoura]

well here is the same thing iam sayin but its aint working its just resizing it to the small size and the 360 size is not workin its kept the same original size :S

$destimg=ImageCreateTrueColor(360,240) or die('Problem In Creating image');
if($userfile_type=="image/gif")
        $srcimg=ImageCreateFromgif($prod_img) or die('Problem In opening Source Image');
if($userfile_type=="image/pjpeg")
        $srcimg=ImageCreateFromJPEG($prod_img) or die('Problem In opening Source Image');
        imagecopyresampled($destimg,$srcimg,0,0,0,0,360,240,ImageSX($srcimg),ImageSY($srcimg)) or die('Problem In resizing');
        ImageJPEG($destimg,$prod_img_thumb,90) or die('Problem In saving');
        imagedestroy($destimg);
//------------------------------------

    $maxwidth=120;
    $new_height= 80;

        $destimg=ImageCreateTrueColor($maxwidth,$new_height) or die('Problem In Creating image');
if($userfile_type=="image/gif")
        $srcimg=ImageCreateFromgif($prod_img) or die('Problem In opening Source Image');
if($userfile_type=="image/pjpeg")
        $srcimg=ImageCreateFromJPEG($prod_img) or die('Problem In opening Source Image');
        imagecopyresampled($destimg,$srcimg,0,0,0,0,$maxwidth,$new_height,ImageSX($srcimg),ImageSY($srcimg)) or die('Problem In resizing');
        ImageJPEG($destimg,$prod_img_thumb,90) or die('Problem In saving');
        imagedestroy($destimg);
 $query=" INSERT INTO IMAGE (ID,Items_ID,image_type,image_size,image_name,thumb_name,image_date) VALUES ('','".$_SESSION['items_id']."','$userfile_type','$userfile_size','$userfile_name','$thumb_name','$time_in')";
mysql_query($query) or die('Error !!'.mysql_error());

    } 

[onion2k]

When you're saving the second file you're using $prod_img_thumb as the filename. That should be $prod_img. Also, check your source and destination image variables are the right way round in the imagecopyresampled() functions .. I'm not sure if you've got them the wrong way round or if you've used odd variable names..