Added AudioFileScanner and AudioImageExtractor logic.

Harmonia.Core/Imaging/AudioImageExtractor.cs

@@ -0,0 +1,27 @@
+using Harmonia.Core.Tags;
+
+namespace Harmonia.Core.Imaging;
+
+public class AudioImageExtractor(ITagResolver tagResolver) : IAudioImageExtractor
+{
+    public SongPictureInfo ExtractImage(string fileName)
+    {
+        SongTagInfo songTagInfo = tagResolver.GetSongTagInfo(fileName);
+
+        return ExtractImage(fileName, songTagInfo);
+    }
+
+    public SongPictureInfo ExtractImage(string fileName, SongTagInfo songTagInfo)
+    {
+        if (songTagInfo.FrontCover != null)
+        {
+            using MemoryStream memoryStream = new(songTagInfo.FrontCover.Data);
+
+            return SongPictureInfo.FromStream(memoryStream);
+        }
+        else
+        {
+            return SongPictureInfo.FromFile(fileName);
+        }
+    }
+}