用php改变背景的颜色

Question

I need to change the color of the background of the ImageCreateTrueColor to white and then put an image on it

elseif(($height>50)&&($width<50))
{
    $img_r = imagecreatefromjpeg($new_img_path); 
    $source = ImageCreateTrueColor(50, 50);
    imagetruecolortopalette($source, FALSE, 2);
    $bg = imagecolorat($source, 0, 0);          
    imagecolorset($source, $bg, 0, 0, 255);
    // $white = imagecolorallocate($source,255,255,255);
    // imagefilledrectangle($source, 0, 0, 50, 50, $white);

    imagecopy($source, $img_r,0,0,0,0,$width,50);
    header('Content-type: image/jpeg');
    imagejpeg($source, $small_new_img_path);

here is the blue, but it doesn't matter, it doesn't put the image on the blue background

Answer 1

You want to create a png not a JPEG. Use imagepng and imagesavealpha.

See full example.