diff --git a/src/calibre/gui2/catalog/catalog_epub_mobi.ui b/src/calibre/gui2/catalog/catalog_epub_mobi.ui
index 858aec429f..044ecdaaec 100644
--- a/src/calibre/gui2/catalog/catalog_epub_mobi.ui
+++ b/src/calibre/gui2/catalog/catalog_epub_mobi.ui
@@ -14,19 +14,6 @@
    <string>Form</string>
   </property>
   <layout class="QGridLayout" name="gridLayout">
-   <item row="0" column="0">
-    <widget class="QLabel" name="label">
-     <property name="text">
-      <string>Tags to exclude as genres (regex):</string>
-     </property>
-     <property name="textFormat">
-      <enum>Qt::LogText</enum>
-     </property>
-     <property name="wordWrap">
-      <bool>true</bool>
-     </property>
-    </widget>
-   </item>
    <item row="1" column="0">
     <widget class="QLabel" name="label_2">
      <property name="text">
@@ -37,7 +24,7 @@
    <item row="1" column="1">
     <widget class="QLineEdit" name="exclude_tags">
      <property name="toolTip">
-      <string extracomment="Tooltip comment here"/>
+      <string extracomment="Default: ~,Catalog"/>
      </property>
     </widget>
    </item>
@@ -51,7 +38,7 @@
    <item row="2" column="1">
     <widget class="QLineEdit" name="read_tag">
      <property name="toolTip">
-      <string extracomment="Tooltip comment here"/>
+      <string extracomment="Default: +"/>
      </property>
     </widget>
    </item>
@@ -65,18 +52,67 @@
    <item row="3" column="1">
     <widget class="QLineEdit" name="note_tag">
      <property name="toolTip">
-      <string extracomment="Tooltip comment here"/>
+      <string extracomment="Default: *"/>
      </property>
     </widget>
    </item>
-   <item row="0" column="1">
+   <item row="8" column="0">
+    <widget class="QCheckBox" name="numbers_as_text">
+     <property name="text">
+      <string>Sort numbers as text</string>
+     </property>
+    </widget>
+   </item>
+   <item row="5" column="1">
     <widget class="QLineEdit" name="exclude_genre">
      <property name="toolTip">
-      <string extracomment="Tooltip comment here"/>
+      <string extracomment="Default: \[[\w]*\]"/>
      </property>
     </widget>
    </item>
-   <item row="4" column="0">
+   <item row="5" column="0">
+    <widget class="QLabel" name="label">
+     <property name="text">
+      <string>Regex pattern describing tags to exclude as genres:</string>
+     </property>
+     <property name="textFormat">
+      <enum>Qt::LogText</enum>
+     </property>
+     <property name="wordWrap">
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
+   <item row="0" column="0" colspan="2">
+    <widget class="QLabel" name="label_5">
+     <property name="font">
+      <font>
+       <pointsize>14</pointsize>
+       <weight>75</weight>
+       <bold>true</bold>
+      </font>
+     </property>
+     <property name="text">
+      <string>Special marker tags for catalog generation</string>
+     </property>
+     <property name="alignment">
+      <set>Qt::AlignCenter</set>
+     </property>
+    </widget>
+   </item>
+   <item row="6" column="1">
+    <widget class="QLabel" name="label_6">
+     <property name="text">
+      <string>Regex tips:
+- The default regex of '\[[\w]*\]' ignores tags of the form '[tag]', e.g., '[Amazon Freebie]'
+- A regex of '.' ignores all tags, generating no genre categories in the catalog</string>
+     </property>
+     <property name="wordWrap">
+      <bool>true</bool>
+     </property>
+    </widget>
+   </item>
+   <item row="7" column="0">
     <spacer name="verticalSpacer">
      <property name="orientation">
       <enum>Qt::Vertical</enum>
@@ -89,13 +125,6 @@
      </property>
     </spacer>
    </item>
-   <item row="5" column="0">
-    <widget class="QCheckBox" name="numbers_as_text">
-     <property name="text">
-      <string>Sort numbers as text</string>
-     </property>
-    </widget>
-   </item>
   </layout>
  </widget>
  <resources/>
diff --git a/src/calibre/gui2/dialogs/catalog.ui b/src/calibre/gui2/dialogs/catalog.ui
index c18e08ef65..3d62f36e85 100644
--- a/src/calibre/gui2/dialogs/catalog.ui
+++ b/src/calibre/gui2/dialogs/catalog.ui
@@ -107,7 +107,7 @@
     <rect>
      <x>12</x>
      <y>12</y>
-     <width>205</width>
+     <width>301</width>
      <height>17</height>
     </rect>
    </property>
diff --git a/src/calibre/web/feeds/news.py b/src/calibre/web/feeds/news.py
index 3328445fd8..00869409ea 100644
--- a/src/calibre/web/feeds/news.py
+++ b/src/calibre/web/feeds/news.py
@@ -872,6 +872,8 @@ class BasicNewsRecipe(Recipe):
         image_ext = name.rpartition('.')[2].lower()
         if image_ext in ['jpg','jpeg']:
             return name
+        if image_ext not in ['gif']:
+            raise RuntimeError("web.feeds.news:BasicNewsRecipe.convert_image(): '%s' is not a supported mastheadImage format" % image_ext)
         import calibre.utils.PythonMagickWand as p
         img = p.NewMagickWand()
         if img < 0:
@@ -880,6 +882,7 @@ class BasicNewsRecipe(Recipe):
             self.log.warn('Failed to read image:', name)
         name = name.replace('.%s' % image_ext, '.jpg')
         p.MagickWriteImage(img, name)
+        p.DestroyMagickWand(img)
         return name
 
     def _download_masthead(self):