Question

I am using this code to convert a Bitmap to Base64:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, **quality**, baos);
byte[] b = baos.toByteArray();
base64code = Base64.encodeToString(b, Base64.DEFAULT);

and receiving it at the server side, this way:

$strImage = preg_replace('!\s*!', '', trim($this->input->post('image')));
        $thefile = base64_decode($strImage);
        $img = imagecreatefromstring($thefile);
        //header('Content-Type: image/jpeg');
        header('Content-Type: bitmap; charset=utf-8');
        imagesavealpha($img, true);
        imagejpeg($img,'./images/temp/testing.jpg',100);
        imagedestroy($img);

Problem:

The actual image size which i am picking from the device gallery to send to the server is 344 kb When i set the quality = 0 and show a spinner dialog util the base64 string is being sent to the server it takes 5 secs to send, and the image received at the server side is 344 Kb but if i am setting quality = 100 it takes 60-70 secs to send, and the image i receive at the server side is 1.7 Mb

Question:

why am i getting the actual size when using quality = 0 and nearly 5 times bigger image when quality = 100

Note:

When i am setting the quality = 100 and change

imagejpeg($img,'./images/temp/testing.jpg',100);

to

imagejpeg($img,'./images/temp/testing.jpg',10);

it takes 60-70 secs to send but the image received on the server side is too small 67 Kb

Thank You

Answer 1

I would think that @EJTH is correct in that 0 might mean to not re-compress the image at all. Any other value (1-100) is probably first converting your image to a bitmap (which would be very large) then compressing to the target quality jpeg. This re-compression takes processing time to complete so you see 60-70 secs for values other than 0.

I’ve not used the Bitmap#compress method before though, so the above is speculation.