I don't understand what you are trying to describe. Please provide a small script to reproduce your problem and add links to images if you need image to illustrate the problem or to show what you would like to achieve.

Basic code :

<?PHP
  
 $image = @imagecreatefrompng('some/some/some.png');

 if ($image === false) {
        die ('Unable to open image');
 }
 
 $color = imagecolorallocate($image, 0, 0, 0);
 imagefill($image, 200, 200, $color);

# Nothing happend on image after thiss command

# From this point on everything work correctly
  imagefill($image, 500, 500, $color);
  
  header("Content-type: image/png");
  header("Content-Disposition: inline; filename=map.png");
  imagepng($image);
  
?>

I have map of country and fill some section with color, then show image in browser.

Please provide the file 'some/some/some.png'

What does that mean:

# Nothing happend on image after thiss command

# From this point on everything work correct
...

I really need a script to *reproduce* your problem.

Sent to your email address

Not a but, not able toreproduce.