diff --git a/4dev/tests/Output/CoreLibsOutputImageTest.php b/4dev/tests/Output/CoreLibsOutputImageTest.php
index 53840934..aa8dff97 100644
--- a/4dev/tests/Output/CoreLibsOutputImageTest.php
+++ b/4dev/tests/Output/CoreLibsOutputImageTest.php
@@ -16,17 +16,89 @@ final class CoreLibsOutputImageTest extends TestCase
 	/**
 	 * Undocumented function
 	 *
-	 * @testdox Output\Image Class tests
+	 * @covers ::createThumbnail
+	 * @testdox createThumbnail checks
 	 *
 	 * @return void
 	 */
-	public function testOutputImage()
+	public function testCreateThumbnail(): void
 	{
-		// $this->assertTrue(true, 'Output Image Tests not implemented');
-		$this->markTestIncomplete(
-			'Output\Image Tests have not yet been implemented'
+		// CONVERT does not exist
+		$this->expectException(\RuntimeException::class);
+		\CoreLibs\Output\Image::createThumbnail('do_not_exist.png', 200, 200);
+		// set convert
+		$paths = [
+			'/bin',
+			'/usr/bin',
+			'/usr/local/bin',
+		];
+		// find convert
+		foreach ($paths as $path) {
+			if (
+				file_exists($path . DIRECTORY_SEPARATOR . 'convert') &&
+				is_file($path . DIRECTORY_SEPARATOR . 'convert')
+			) {
+				// image magick convert location
+				define('CONVERT', $path . DIRECTORY_SEPARATOR . 'convert');
+				break;
+			}
+		}
+		unset($paths);
+		// cannot set dummy file
+		$this->expectException(\Exception::class);
+		\CoreLibs\Output\Image::createThumbnail('do_not_exist.png', 200, 200);
+	}
+
+	/**
+	 * Undocumented function
+	 *
+	 * @covers ::createThumbnailSimple
+	 * @testdox createThumbnailSimple checks
+	 *
+	 * @return void
+	 */
+	public function testCreateThumbnailSimple(): void
+	{
+		// file does not exist
+		$this->expectException(\UnexpectedValueException::class);
+		\CoreLibs\Output\Image::createThumbnailSimple(
+			'do_not_exist.png',
+			200,
+			200,
+			cache_folder: '/tmp/',
+			web_folder: '/tmp/'
 		);
-		// $this->markTestSkipped('No implementation for Output\Image at the moment');
+		// cache folder is not dir
+		$this->expectException(\UnexpectedValueException::class);
+		\CoreLibs\Output\Image::createThumbnailSimple(
+			'do_not_exist.png',
+			200,
+			200,
+			cache_folder: '/foo/bar/',
+			web_folder: '/tmp/'
+		);
+		// target cache folder is not writeable
+
+		// RuntimeException: imagecreatetruecolor failed
+		// RuntimeException: imagecolorallocatealpha failed
+	}
+
+	/**
+	 * Undocumented function
+	 *
+	 * @covers ::correctImageOrientation
+	 * @testdox correctImageOrientation checks
+	 *
+	 * @return void
+	 */
+	public function testCorrectImageOrientation(): void
+	{
+		// test file does not exist
+		$this->expectException(\UnexpectedValueException::class);
+		\CoreLibs\Output\Image::correctImageOrientation('do_not_exist.png');
+		// test folder not writeable
+		// test exit_read_data not present (how)?
+		// test image rotate
 	}
 }
 
diff --git a/www/admin/class_test.image.php b/www/admin/class_test.image.php
index d2be61c6..0ae756ba 100644
--- a/www/admin/class_test.image.php
+++ b/www/admin/class_test.image.php
@@ -46,7 +46,13 @@ $image = BASE . LAYOUT . CONTENT_PATH . IMAGES . 'no_picture_square.jpg';
 $cache_folder = BASE . LAYOUT . CONTENT_PATH . CACHE . IMAGES;
 $web_folder = LAYOUT . CACHE . IMAGES;
 // rotate image first
-$_image->correctImageOrientation($image);
+try {
+	$_image->correctImageOrientation($image);
+} catch (\UnexpectedValueException $e) {
+	print "Message:<br>" . $e->getMessage() . "<br>" . $e . "<br>";
+} catch (\RuntimeException $e) {
+	print "Message:<br>" . $e->getMessage() . "<br>" . $e . "<br>";
+}
 // thumbnail tests
 echo "<div>CLASS->CREATETHUMBNAILSIMPLE: "
 	. basename($image) . ": WIDTH: $thumb_width<br><img src="
@@ -54,7 +60,13 @@ echo "<div>CLASS->CREATETHUMBNAILSIMPLE: "
 // static
 $image = BASE . LAYOUT . CONTENT_PATH . IMAGES . 'no_picture.jpg';
 // rotate image first
-$image_class::correctImageOrientation($image);
+try {
+	$image_class::correctImageOrientation($image);
+} catch (\UnexpectedValueException $e) {
+	print "Message:<br>" . $e->getMessage() . "<br>" . $e . "<br>";
+} catch (\RuntimeException $e) {
+	print "Message:<br>" . $e->getMessage() . "<br>" . $e . "<br>";
+}
 // thumbnail tests
 echo "<div>S::CREATETHUMBNAILSIMPLE: "
 	. basename($image) . ": WIDTH: $thumb_width<br><img src="
@@ -87,7 +99,13 @@ foreach ($images as $image) {
 	echo "<div><b>IMAGE INFO</b>: " . $height . "x" . $width . ", TYPE: "
 		. \CoreLibs\Debug\Support::dumpVar($img_type) . " [" . $finfo->file($image) . "]</div>";
 	// rotate image first
-	Image::correctImageOrientation($image);
+	try {
+		Image::correctImageOrientation($image);
+	} catch (\UnexpectedValueException $e) {
+		print "Message:<br>" . $e->getMessage() . "<br>" . $e . "<br>";
+	} catch (\RuntimeException $e) {
+		print "Message:<br>" . $e->getMessage() . "<br>" . $e . "<br>";
+	}
 	// thumbnail tests
 	echo "<div>" . basename($image) . ": WIDTH: $thumb_width<br><img src="
 		. Image::createThumbnailSimple($image, $thumb_width, 0, $cache_folder, $web_folder) . "></div>";
diff --git a/www/lib/CoreLibs/Output/Image.php b/www/lib/CoreLibs/Output/Image.php
index 5af6ce3f..897e6495 100644
--- a/www/lib/CoreLibs/Output/Image.php
+++ b/www/lib/CoreLibs/Output/Image.php
@@ -470,12 +470,20 @@ class Image
 	 *
 	 * @param  string $filename path + filename to rotate. This file must be writeable
 	 * @return void
+	 * @throws \RuntimeException if exit_read_data is not found
+	 * @throws \UnexpectedValueException if file name not writeable or file name not found
 	 */
 	public static function correctImageOrientation(string $filename): void
 	{
 		// function exists & file is writeable, else do nothing
-		if (!function_exists('exif_read_data') || !is_writeable($filename)) {
-			return;
+		if (!function_exists('exif_read_data')) {
+			throw new \RuntimeException('Function \'exit_read_data\' does not exist');
+		}
+		if (!file_exists($filename) || !is_file($filename)) {
+			throw new \UnexpectedValueException('Missing image file: ' . $filename);
+		}
+		if (!is_writeable($filename)) {
+			throw new \UnexpectedValueException('File name is not writeable: ' . $filename);
 		}
 		[$inc_width, $inc_height, $img_type] = getimagesize($filename) ?: [0, 0, null];
 		// add @ to avoid "file not supported error"