Add a Save Image option to the Reader context menu.

lib/pages/reader/gesture.dart

@@ -287,6 +287,12 @@ class _ReaderGestureDetectorState extends AutomaticGlobalState<_ReaderGestureDet
             text: "Copy Image".tl,
             onClick: () => copyImage(location),
           ),
+        if (!reader.isLoading)
+          MenuEntry(
+            icon: Icons.download_outlined,
+            text: "Save Image".tl,
+            onClick: () => saveImage(location),
+          ),
       ],
     );
   }
@@ -319,6 +325,17 @@ class _ReaderGestureDetectorState extends AutomaticGlobalState<_ReaderGestureDet
       context.showMessage(message: "No Image");
     }
   }
+
+  void saveImage(Offset location) async {
+    var controller = reader._imageViewController;
+    var image = await controller!.getImageByOffset(location);
+    if (image != null) {
+      var filetype = detectFileType(image);
+      saveFile(filename: "image${filetype.ext}", data: image);
+    } else {
+      context.showMessage(message: "No Image");
+    }
+  }
 }
 
 class _DragListener {

lib/pages/reader/scaffold.dart

@@ -378,11 +378,12 @@ class _ReaderScaffoldState extends State<_ReaderScaffold> {
               Tooltip(
                 message: "Collect the image".tl,
                 child: IconButton(
-                    icon: Icon(
+                  icon:
-                        isLiked() ? Icons.favorite : Icons.favorite_border),
+                      Icon(isLiked() ? Icons.favorite : Icons.favorite_border),
-                    onPressed: addImageFavorite),
+                  onPressed: addImageFavorite,
                 ),
-              if (App.isWindows)
+              ),
+              if (App.isDesktop)
                 Tooltip(
                   message: "${"Full Screen".tl}(F12)",
                   child: IconButton(
@@ -750,9 +751,7 @@ class _ReaderScaffoldState extends State<_ReaderScaffold> {
                       ? Icons.arrow_forward_ios
                       : Icons.arrow_back_ios_outlined,
                   size: 24,
-                  color: Theme.of(context)
+                  color: Theme.of(context).colorScheme.onPrimaryContainer,
-                      .colorScheme
-                      .onPrimaryContainer,
                 ),
               ),
             ),