diff --git a/inc/Service/Media/LibMagickMediaHandler.php b/inc/Service/Media/LibMagickMediaHandler.php
index a2a44c91..3514783b 100644
--- a/inc/Service/Media/LibMagickMediaHandler.php
+++ b/inc/Service/Media/LibMagickMediaHandler.php
@@ -20,6 +20,7 @@ class LibMagickMediaHandler implements MediaHandler {
 	private bool $frames_for_gif_thumbs;
 	private int $image_max_width;
 	private int $image_max_height;
+	private string $static_thumb_mime;
 
 
 	private static function degreesFromOrientation(int $orientation): int {
@@ -86,7 +87,6 @@ class LibMagickMediaHandler implements MediaHandler {
 		\Imagick $imagick,
 		string $source_file_mime,
 		string $preferred_out_file_basepath,
-		string $preferred_out_mime,
 		int $width,
 		int $height,
 		int $max_width,
@@ -163,7 +163,7 @@ class LibMagickMediaHandler implements MediaHandler {
 				$thumb_height = $height;
 			}
 
-			$out_ext = Metadata\mime_to_ext($preferred_out_mime);
+			$out_ext = Metadata\mime_to_ext($this->static_thumb_mime);
 			$out_path = $preferred_out_file_basepath . '.' . $out_ext;
 
 			$imagick->stripImage();
@@ -172,7 +172,7 @@ class LibMagickMediaHandler implements MediaHandler {
 
 			return new ThumbGenerationResult(
 				$out_path,
-				$preferred_out_mime,
+				$this->static_thumb_mime,
 				$thumb_width,
 				$thumb_height
 			);
@@ -194,11 +194,12 @@ class LibMagickMediaHandler implements MediaHandler {
 		return false;
 	}
 
-	public function __construct(bool $strip_metadata, int $frames_for_gif_thumbs, int $max_width, int $max_height) {
+	public function __construct(bool $strip_metadata, int $frames_for_gif_thumbs, int $max_width, int $max_height, string $static_thumb_mime) {
 		$this->strip_metadata = $strip_metadata;
 		$this->frames_for_gif_thumbs = $frames_for_gif_thumbs;
 		$this->image_max_width = $max_width;
 		$this->image_max_height = $max_height;
+		$this->static_thumb_mime = $static_thumb_mime;
 	}
 
 	public function supportsMime(string $mime): bool {
@@ -246,7 +247,6 @@ class LibMagickMediaHandler implements MediaHandler {
 	public function generateThumb(
 		mixed $handle,
 		string $preferred_out_file_basepath,
-		string $preferred_out_mime,
 		int $max_width,
 		int $max_height
 	): ThumbGenerationResult {
@@ -270,7 +270,6 @@ class LibMagickMediaHandler implements MediaHandler {
 				$imagick,
 				$source_file_mime,
 				$preferred_out_file_basepath,
-				$preferred_out_mime,
 				$width,
 				$height,
 				$max_width,
@@ -283,7 +282,6 @@ class LibMagickMediaHandler implements MediaHandler {
 		mixed $handle,
 		string $media_preferred_out_file_basepath,
 		string $thumb_preferred_out_file_basepath,
-		string $thumb_preferred_out_mime,
 		int $thumb_max_width,
 		int $thumb_max_height
 	): MediaInstallResult {
@@ -308,7 +306,6 @@ class LibMagickMediaHandler implements MediaHandler {
 					$imagick,
 					$media_file_mime,
 					$thumb_preferred_out_file_basepath,
-					$thumb_preferred_out_mime,
 					$width,
 					$height,
 					$thumb_max_width,
@@ -334,7 +331,6 @@ class LibMagickMediaHandler implements MediaHandler {
 				$imagick,
 				$media_file_mime,
 				$thumb_preferred_out_file_basepath,
-				$thumb_preferred_out_mime,
 				$width,
 				$height,
 				$thumb_max_width,