GD resample to lower file size

ijasont

Hello,
I have been searching for this forever with no luck.

I need to find a way to lower the total file size (as in mb or kb) while leaving the image size alone.

in other words I need to make an 800x600 4mb jpeg into an 800x600 2mb jpeg.

all the tutorials I have seen are only on adjusting the image size NOT the file size.

I know this can be done, I just dont know how to do it.,

sidney

// create image from file
$image='test.jpg';
$im=imagecreatefromjpeg($image);
//save image back to file at lower quality
imagejpeg($im,$image,50);

the 50 is the quaulity from 0 to 100

imagejpeg

ijasont

thanks for the reply. That function seems to only work on image output though is that correct?

While Im pretty good at PHP I really am a GD n00b so sorry about this.

What I would like is a script that can take a file. Get the image file size. If size is larger than XX then it reduces the quality by 10% then checks again and cycles until size => XX.

Can your listed function help me do this?

onion2k

Yes it can.

$quality = 100;
$filesize = 50000;
while ($filesize >= 50000 and $quality >= 5) {
  $quality = $quality - 5;
  imagejpeg($image,"image.jpg",$quality);
  $filesize = filesize("image.jpg");
}

Roughly. I've not tested that.