-[#1060] Added toggle to disable thumbnail loading.

-Added button to wipe metadata cache.
-Added more paddings on player buttons.
-Added new animations to main player secondary controls and play queue expand/collapse.
-Refactored play queue item touch callback for use in all players.
-Improved MediaSourceManager to better handle expired stream reloading.
-[#1186] Changed live sync button text to "LIVE".
-Removed MediaSourceManager loader coupling on main players.
-Moved service dependent expiry resolution to ServiceHelper.
-[#1186] Fixed livestream timeline updates causing negative time position.
-[#1186] Fixed livestream not starting from live-edge.
-Fixed main player system UI not retracting on playback start.

app/src/main/java/org/schabi/newpipe/ImageDownloader.java

@@ -1,25 +1,40 @@
 package org.schabi.newpipe;
 
 import android.content.Context;
+import android.content.SharedPreferences;
+import android.preference.PreferenceManager;
 
 import com.nostra13.universalimageloader.core.download.BaseImageDownloader;
 
 import org.schabi.newpipe.extractor.NewPipe;
 
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 
 public class ImageDownloader extends BaseImageDownloader {
+    private static final ByteArrayInputStream DUMMY_INPUT_STREAM =
+            new ByteArrayInputStream(new byte[]{});
+
+    private final SharedPreferences preferences;
+    private final String downloadThumbnailKey;
+
     public ImageDownloader(Context context) {
         super(context);
+        this.preferences = PreferenceManager.getDefaultSharedPreferences(context);
+        this.downloadThumbnailKey = context.getString(R.string.download_thumbnail_key);
     }
 
-    public ImageDownloader(Context context, int connectTimeout, int readTimeout) {
-        super(context, connectTimeout, readTimeout);
+    private boolean isDownloadingThumbnail() {
+        return preferences.getBoolean(downloadThumbnailKey, true);
     }
 
     protected InputStream getStreamFromNetwork(String imageUri, Object extra) throws IOException {
-        Downloader downloader = (Downloader) NewPipe.getDownloader();
-        return downloader.stream(imageUri);
+        if (isDownloadingThumbnail()) {
+            final Downloader downloader = (Downloader) NewPipe.getDownloader();
+            return downloader.stream(imageUri);
+        } else {
+            return DUMMY_INPUT_STREAM;
+        }
     }
 }