https://placehold.it/70x70

https://albertobsd.dev/random?format=img&w=70&h=70

<?php
	$h = 100;
	$w = 100;
	if(isset($_GET["w"]) && intval($_GET["w"]) > 0)	{
		$w = intval($_GET["w"]);
	}
	if(isset($_GET["h"]) && intval($_GET["h"]) > 0)	{
		$h = intval($_GET["h"]);
	}
	$im = imagecreate($w, $h);
	$gray = imagecolorallocate ($im , 50 , 50 , 50 );
	imagefill( $im ,$w , $h , $gray );
	header("Cache-Control: no-cache, no-store, must-revalidate");
	header("Pragma: no-cache");
	header("Expires: 0");	
	header("Content-type: image/png");
	imagepng($im);
	imagedestroy($im);
?>

<?php
	$h = 100;
	$w = 100;
	if(isset($_GET["w"]) && intval($_GET["w"]) > 0)	{
		$w = intval($_GET["w"]);
	}
	if(isset($_GET["h"]) && intval($_GET["h"]) > 0)	{
		$h = intval($_GET["h"]);
	}
	$im = imagecreate($w, $h);
	$gray = imagecolorallocate ($im , 50 , 50 , 50 );
	$white = imagecolorallocate ($im , 255 , 255 , 255 );
	if(imagefill( $im ,$w , $h , $gray ))	{
		header("Imagefill: OK");
	}
	header("Cache-Control: no-cache, no-store, must-revalidate");
	header("Pragma: no-cache");
	header("Expires: 0");	
	header("Content-type: image/png");
	$tfile = tempnam("/tmp","FOO");
	if(imagepng($im,$tfile,0))	{
		header("Imagepng: OK");
	}
	if(imagedestroy($im))	{
		header("Imagedestroy: OK");
	}
	header("N: $tfile");
	header('Content-Length: ' . filesize($tfile));
	readfile($tfile);
	unlink($tfile);
?>

$ file /tmp/FOOxOdebm
/tmp/FOOxOdebm: PNG image data, 750 x 300, 1-bit colormap, non-interlaced