Image::clone() uses PNG format because GD2 is disabled since libgd 2.3.3

Author: dg

src/Utils/Image.php

@@ -735,7 +735,7 @@ public function __call(string $name, array $args)
 	public function __clone()
 	{
 		ob_start(function () {});
-		imagegd2($this->image);
+		imagepng($this->image, null, 0);
 		$this->setImageResource(imagecreatefromstring(ob_get_clean()));
 	}
 

tests/Utils/Image.clone.phpt

@@ -18,4 +18,7 @@ $original = Image::fromFile(__DIR__ . '/fixtures.images/logo.gif');
 
 $dolly = clone $original;
 Assert::notSame($dolly->getImageResource(), $original->getImageResource());
-Assert::same($dolly->toString(Image::GIF), $original->toString(Image::GIF));
+Assert::same($dolly->getHeight(), $original->getHeight());
+Assert::same($dolly->getWidth(), $original->getWidth());
+Assert::same($dolly->isTrueColor(), $original->isTrueColor());
+Assert::same($dolly->toString(Image::PNG), $original->toString(Image::PNG));