[imgur] Simplify

youtube_dl/extractor/imgur.py

@@ -5,12 +5,12 @@ import re
 from .common import InfoExtractor
 from ..utils import (
     int_or_none,
-    str_or_none,
     js_to_json,
     mimetype2ext,
     ExtractorError,
 )
 
+
 class ImgurIE(InfoExtractor):
     _VALID_URL = r'https?://(?:i\.)?imgur\.com/(?P<id>[a-zA-Z0-9]+)(?:\.mp4|\.gifv)?'
 
@@ -43,12 +43,13 @@ class ImgurIE(InfoExtractor):
             r'<param name="height" value="([0-9]+)"',
             webpage, 'height', fatal=False))
 
-        video_elements = str_or_none(self._search_regex(
+        video_elements = self._search_regex(
             r'(?s)<div class="video-elements">(.*?)</div>',
-            webpage, 'video elements', fatal=False))
+            webpage, 'video elements', default=None)
         if not video_elements:
             raise ExtractorError(
-                'No sources found for video %s' % video_id, expected=True)
+                'No sources found for video %s. Maybe an image?' % video_id,
+                expected=True)
 
         formats = []
         for m in re.finditer(r'<source\s+src="(?P<src>[^"]+)"\s+type="(?P<type>[^"]+)"', video_elements):