diff --git a/youtube_dl/extractor/archiveorg.py b/youtube_dl/extractor/archiveorg.py
index c79c58e82..0d69d9ad5 100644
--- a/youtube_dl/extractor/archiveorg.py
+++ b/youtube_dl/extractor/archiveorg.py
@@ -48,6 +48,10 @@ class ArchiveOrgIE(InfoExtractor):
 
         def get_optional(metadata, field):
             return metadata.get(field, [None])[0]
+        
+        def convert_relative_to_absolute_thumbnail(metadata):
+            if not metadata['thumbnail'].startswith('http'):
+                metadata.update({'thumbnail': ''.join(('http://archive.org', metadata.get('thumbnail')))})
 
         metadata = self._download_json(
             'http://archive.org/details/' + video_id, video_id, query={
@@ -62,4 +66,8 @@ class ArchiveOrgIE(InfoExtractor):
                 'uploader': get_optional(metadata, 'creator'),
                 'upload_date': unified_strdate(get_optional(metadata, 'date')),
             })
-        return info
+            convert_relative_to_absolute_thumbnail(info)
+        else:
+            for entry in info['entries']:
+                convert_relative_to_absolute_thumbnail(entry)
+        return info
\ No newline at end of file