Infer video thumbnail format from image format

src/generate.rs

@@ -201,7 +201,7 @@ where
         let (reader, media_type) = if let Some(processable_format) =
             original_details.internal_format().processable_format()
         {
-            let thumbnail_format = ImageFormat::Jpeg;
+            let thumbnail_format = media.image.format.unwrap_or(ImageFormat::Webp);
 
             let reader = magick::thumbnail(
                 store,
@@ -215,7 +215,13 @@ where
 
             (reader, thumbnail_format.media_type())
         } else {
-            let thumbnail_format = ffmpeg::ThumbnailFormat::Jpeg;
+            let thumbnail_format = match media.image.format {
+                Some(ImageFormat::Webp | ImageFormat::Avif | ImageFormat::Jxl) => {
+                    ffmpeg::ThumbnailFormat::Webp
+                }
+                Some(ImageFormat::Png) => ffmpeg::ThumbnailFormat::Png,
+                Some(ImageFormat::Jpeg) | None => ffmpeg::ThumbnailFormat::Jpeg,
+            };
 
             let reader = ffmpeg::thumbnail(
                 store.clone(),

src/generate/ffmpeg.rs

@@ -8,35 +8,39 @@ use crate::{
 #[derive(Clone, Copy, Debug)]
 pub(super) enum ThumbnailFormat {
     Jpeg,
-    // Webp,
+    Png,
+    Webp,
 }
 
 impl ThumbnailFormat {
     const fn as_ffmpeg_codec(self) -> &'static str {
         match self {
             Self::Jpeg => "mjpeg",
-            // Self::Webp => "webp",
+            Self::Png => "png",
+            Self::Webp => "webp",
         }
     }
 
     const fn to_file_extension(self) -> &'static str {
         match self {
             Self::Jpeg => ".jpeg",
-            // Self::Webp => ".webp",
+            Self::Png => ".png",
+            Self::Webp => ".webp",
         }
     }
 
     const fn as_ffmpeg_format(self) -> &'static str {
         match self {
-            Self::Jpeg => "image2",
+            Self::Jpeg | Self::Png => "image2",
-            // Self::Webp => "webp",
+            Self::Webp => "webp",
         }
     }
 
     pub(crate) fn media_type(self) -> mime::Mime {
         match self {
             Self::Jpeg => mime::IMAGE_JPEG,
-            // Self::Webp => crate::formats::mimes::image_webp(),
+            Self::Png => mime::IMAGE_PNG,
+            Self::Webp => crate::formats::mimes::image_webp(),
         }
     }
 }