From f3845be39fe154e08b5bd6cc2a162fc119a69edf Mon Sep 17 00:00:00 2001
From: the-djmaze <>
Date: Tue, 28 Mar 2023 15:06:05 +0200
Subject: [PATCH] Fix GD2 for #1009

---
 snappymail/v/0.0.0/app/libraries/snappymail/image/gd2.php | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/snappymail/v/0.0.0/app/libraries/snappymail/image/gd2.php b/snappymail/v/0.0.0/app/libraries/snappymail/image/gd2.php
index b4dd61aab..3f496b3f8 100644
--- a/snappymail/v/0.0.0/app/libraries/snappymail/image/gd2.php
+++ b/snappymail/v/0.0.0/app/libraries/snappymail/image/gd2.php
@@ -50,7 +50,8 @@ class GD2 implements \SnappyMail\Image
 		}
 		$gd2 = new static();
 		$gd2->img = \imagecreatefromstring($data);
-		if (!\is_resource($gd2->img)) {
+		// resource or PHP8 GdImage
+		if (!$gd2->img) {
 			throw new \InvalidArgumentException('Failed to load image');
 		}
 		$gd2->file = 'blob';
@@ -223,7 +224,7 @@ class GD2 implements \SnappyMail\Image
 		/** rotate clockwise */
 		if (!\function_exists('imagerotate')) { require __DIR__ . '/gd2/imagerotate.inc'; }
 		$tmp_img = \imagerotate($this->img, $degrees * -1, 0);
-		if (!\is_resource($tmp_img)) { return false; }
+		if (!$tmp_img) { return false; }
 		\imagedestroy($this->img);
 		$this->img = $tmp_img;
 		return true;
@@ -240,7 +241,7 @@ class GD2 implements \SnappyMail\Image
 		if (!$width  || ($bestfit && $tx < $ty)) { $width  = \round($x / $ty); }
 		if (!$height || ($bestfit && $tx > $ty)) { $height = \round($y / $tx); }
 		$tmp_img = $this->create_image($width, $height);
-		if (!\is_resource($tmp_img)) { return false; }
+		if (!$tmp_img) { return false; }
 		\imagealphablending($tmp_img, false);
 		if (!\imagecopyresampled($tmp_img, $this->img, 0, 0, 0, 0, $width, $height, $x, $y)) {
 			if (!\imagecopyresized($tmp_img, $this->img, 0, 0, 0, 0, $width, $height, $x, $y)) {