Question

When i resample a jpg in order to draw border around the image, the quality of image is horribly decreases and extremely low quality jpeg is gotten.

Here is my code:

function addBorderpng($add,$bdr=0,$color='#000000'){
                $arr = explode('.', $add);
                $extension = strtolower(end($arr));
                $border=$bdr;

$im=imagecreatefromjpeg($add);

                $width=imagesx($im);
                $height=imagesy($im);
                $img_adj_width=$width+(2*$border);
                $img_adj_height=$height+(2*$border);
                $newimage=imagecreatetruecolor($img_adj_width,$img_adj_height);

                imageantialias($newimage, true);
                $color_gb_temp =HexToRGB($color);
                $border_color = imagecolorallocate($newimage, $color_gb_temp['r'], $color_gb_temp['g'], $color_gb_temp['b']);
                imagefilledrectangle($newimage,0,0,$img_adj_width,$img_adj_height,$border_color);
                imagealphablending($newimage, true);
                imageantialias($newimage, true);
                     imagecopyresized($newimage,$im,$border,$border,0,0,$width,$height,$width,$height);
                    imagejpeg($newimage,$add,9);
            }

Answer 1

The last argument to imagejpeg is quality.

quality is optional, and ranges from 0 (worst quality, smaller file) to 100 (best quality, biggest file). The default is the default IJG quality value (about 75).

You are setting it at 9, hence low quality.