Problem pasting one image into another PHP

I want to paste the $original image into the center of $fondo image, i write the following code:

<?php
header('Content-Type: image/png');

// The file

$fondo = imagecreate(1000,1000); // Create 1000x1000 image
$color_fondo = imagecolorallocate($fondo,197,237,206); // Set color of background
$original = imagecreatefromstring(file_get_contents('test.jpg')); // Load image

$wb = imagesx($fondo); // Bakground width
$wi = imagesx($original); // Image width
$hb = imagesy($fondo);
$hi = imagesy($original);


//Want to center in the middle of the image, so calc ($wb/2-$wi/2)
imagecopy($fondo,$original,($wb/2-$wi/2),($hb/2-$hi/2),0,0,imagesx($original),imagesy($original));
imagepng($fondo);

The result i got is this:

As you can see the cyan color is affecting original image:

Any ideas on what i’m wrong? Thank you!

Answer

the solution is:

Creating the image as imagecreatetruecolor instead of imagecreate

$fondo = imagecreatetruecolor(1000,1000); // Create 1000x1000 image

$color_fondo = imagecolorallocate($fondo,197,237,206); //Desired color

Then, need to paint the $fondo with imagefill($fondo,0,0,$color_fondo);

Also, crop as circle using this function

function circulo ($original,$radio){


   
    $src = imagecreatefromstring(file_get_contents($original));
    $w = imagesx($src);
    $h = imagesy($src);

    $newpic = imagecreatetruecolor($w,$h);
    imagealphablending($newpic,false);
    $transparent = imagecolorallocatealpha($newpic, 0, 0, 0, 127); //Hacer transparente la imagen

    $r=$w/$radio; //Radio del circulo 
    for($x=0;$x<$w;$x++)
        for($y=0;$y<$h;$y++){
            $c = imagecolorat($src,$x,$y);
            $_x = $x - $w/2;
           // echo $_x."n";
            
            $_y = $y - $h/2;
            if((($_x*$_x) + ($_y*$_y)) < ($r*$r)){
                imagesetpixel($newpic,$x,$y,$c);
            }else{
                imagesetpixel($newpic,$x,$y,$transparent);
            }
        }
    
    return $newpic;
}

The result is :