handle all 8 Exif orientations

Program.cs

@@ -386,12 +386,20 @@ public static class Util {
 
   // https://sirv.com/help/articles/rotate-photos-to-be-upright/
   public static void RotateImageFromExif(Image<Rgba32> image, ushort orientation) {
-    if (orientation == 1) {
+    if (orientation <= 1) {
       return;
     }
-    if (orientation == 8) {
-      image.Mutate(x => x.RotateFlip(RotateMode.Rotate270, FlipMode.None));
-    }
+    var operations = new Dictionary<ushort, (RotateMode, FlipMode)> {
+      { 2, (RotateMode.None, FlipMode.Horizontal) },
+      { 3, (RotateMode.Rotate180, FlipMode.None) },
+      { 4, (RotateMode.Rotate180, FlipMode.Horizontal) },
+      { 5, (RotateMode.Rotate90, FlipMode.Vertical) },
+      { 6, (RotateMode.Rotate90, FlipMode.None) },
+      { 7, (RotateMode.Rotate270, FlipMode.Vertical) },
+      { 8, (RotateMode.Rotate270, FlipMode.None) },
+    };
+    var (rotate, flip) = operations[orientation];
+    image.Mutate(x => x.RotateFlip(rotate, flip));
   }
 
   public static Texture RenderText(string text) {