Adjust logic of cloner transparency application

src/Drivers/Gd/Cloner.php

@@ -5,6 +5,7 @@
 namespace Intervention\Image\Drivers\Gd;
 
 use GdImage;
+use Intervention\Image\Colors\Rgb\Channels\Alpha;
 use Intervention\Image\Colors\Rgb\Color;
 use Intervention\Image\Exceptions\ColorException;
 use Intervention\Image\Geometry\Rectangle;
@@ -67,7 +68,9 @@ public static function cloneEmpty(
         imagealphablending($clone, true);
         imagesavealpha($clone, true);
 
-        if ($background->isClear()) {
+        // set background image as transparent if alpha channel value if color is below .5
+        // comes into effect when the end format only supports binary transparency (like GIF)
+        if ($background->channel(Alpha::class)->value() < 128) {
             imagecolortransparent($clone, $processor->colorToNative($background));
         }