Possibly fixing some freezes and crashes

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaDetailsPresenter.kt

@@ -347,7 +347,7 @@ class MangaDetailsPresenter(
      * @param chapters the list of chapters to download.
      */
     fun downloadChapters(chapters: List<ChapterItem>) {
-        downloadManager.downloadChapters(manga, chapters)
+        downloadManager.downloadChapters(manga, chapters.filter { !it.isDownloaded })
     }
 
     fun restartDownloads() {

app/src/main/java/eu/kanade/tachiyomi/util/system/ImageUtil.kt

@@ -55,8 +55,9 @@ object ImageUtil {
         return null
     }
 
-    fun autoSetBackground(image: Bitmap, useWhiteAlways: Boolean): Drawable {
+    fun autoSetBackground(image: Bitmap?, useWhiteAlways: Boolean): Drawable {
         val backgroundColor = if (useWhiteAlways) Color.WHITE else android.R.attr.colorBackground
+        if (image == null) return ColorDrawable(backgroundColor)
         if (image.width < 50 || image.height < 50)
             return ColorDrawable(backgroundColor)
         val top = 5