diff --git a/SourceGen/RuntimeData/Help/visualization.html b/SourceGen/RuntimeData/Help/visualization.html
index c084789..4407b2b 100644
--- a/SourceGen/RuntimeData/Help/visualization.html
+++ b/SourceGen/RuntimeData/Help/visualization.html
@@ -132,7 +132,8 @@ arrangements are common.  The script defines three generators:</p>
     bitmaps.  This is intended for hi-res fonts, which are typically
     8 bytes per entry, stored one after another.  These are always
     converted as monochrome, and have a 1-pixel transparent gap
-    between elements.</li>
+    between elements.  (This also works for Apple /// fonts, but
+    currently ignores the high bit in each byte.)</li>
   <li><b>Hi-Res Screen Image</b> - used for 8KiB screen images.  The
     data is linearized and converted to a 280x192 bitmap.  Because
     images are relatively large, the generator does not require them
diff --git a/SourceGen/WpfGui/EditVisualization.xaml b/SourceGen/WpfGui/EditVisualization.xaml
index 8bea361..683f024 100644
--- a/SourceGen/WpfGui/EditVisualization.xaml
+++ b/SourceGen/WpfGui/EditVisualization.xaml
@@ -97,6 +97,7 @@ limitations under the License.
             <RowDefinition Height="*"/>
             <RowDefinition Height="Auto"/>
             <RowDefinition Height="Auto"/>
+            <RowDefinition Height="Auto"/>
         </Grid.RowDefinitions>
 
         <Grid Grid.Row="0">
@@ -136,7 +137,12 @@ limitations under the License.
                    RenderOptions.BitmapScalingMode="NearestNeighbor"/>
         </Border>
 
-        <Grid Grid.Row="2" HorizontalAlignment="Left">
+        <StackPanel Grid.Row="2" Orientation="Horizontal" HorizontalAlignment="Right">
+                <TextBlock FontSize="10" Text="Bitmap size: "/>
+                <TextBlock FontSize="10" Text="{Binding BitmapDimensions, FallbackValue=32x64}"/>
+        </StackPanel>
+
+        <Grid Grid.Row="3" HorizontalAlignment="Left">
             <Grid.RowDefinitions>
                 <RowDefinition Height="Auto"/>
                 <RowDefinition Height="Auto"/>
@@ -145,7 +151,7 @@ limitations under the License.
 
             <StackPanel Grid.Row="0" Orientation="Horizontal" Margin="0,0,0,4">
                 <!--<TextBlock Text="Message:" Margin="0,0,8,0"/>-->
-                <TextBlock Text="{Binding PluginErrMessage}" Foreground="Red"/>
+                <TextBlock Text="{Binding PluginErrMessage, FallbackValue=ERROR}" Foreground="Red"/>
             </StackPanel>
 
             <TextBlock Grid.Row="1" Text="Parameters:" Margin="0,0,0,4"/>
@@ -157,7 +163,7 @@ limitations under the License.
             </ItemsControl>
         </Grid>
         
-        <DockPanel Grid.Column="0" Grid.Row="3" Margin="0,8,0,0" LastChildFill="False">
+        <DockPanel Grid.Column="0" Grid.Row="4" Margin="0,8,0,0" LastChildFill="False">
             <Button DockPanel.Dock="Right" Content="Cancel" Width="70" Margin="8,0,0,0" IsCancel="True"/>
             <Button DockPanel.Dock="Right" Grid.Column="1" Content="OK" Width="70"
                     IsDefault="True" IsEnabled="{Binding IsValid}" Click="OkButton_Click"/>
diff --git a/SourceGen/WpfGui/EditVisualization.xaml.cs b/SourceGen/WpfGui/EditVisualization.xaml.cs
index b329239..4622ba1 100644
--- a/SourceGen/WpfGui/EditVisualization.xaml.cs
+++ b/SourceGen/WpfGui/EditVisualization.xaml.cs
@@ -23,6 +23,7 @@ using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
+
 using Asm65;
 using PluginCommon;
 
@@ -70,6 +71,7 @@ namespace SourceGen.WpfGui {
         }
         private string mTagString;
 
+        // Text turns red on error.
         public Brush TagLabelBrush {
             get { return mTagLabelBrush; }
             set { mTagLabelBrush = value; OnPropertyChanged(); }
@@ -112,6 +114,13 @@ namespace SourceGen.WpfGui {
         /// </summary>
         public string LastPluginMessage { get; set; }
 
+        // Bitmap width/height indicator.
+        public string BitmapDimensions {
+            get { return mBitmapDimensions; }
+            set { mBitmapDimensions = value; OnPropertyChanged(); }
+        }
+        private string mBitmapDimensions;
+
         /// <summary>
         /// ItemsSource for the ItemsControl with the generated parameter controls.
         /// </summary>
@@ -417,6 +426,7 @@ namespace SourceGen.WpfGui {
 
             VisualizationItem item = (VisualizationItem)visComboBox.SelectedItem;
 
+            BitmapDimensions = "?";
             if (!IsValid || item == null) {
                 previewImage.Source = sBadParamsImage;
             } else {
@@ -448,6 +458,8 @@ namespace SourceGen.WpfGui {
                     IsValid = false;
                 } else {
                     previewImage.Source = Visualization.ConvertToBitmapSource(vis2d);
+                    BitmapDimensions = string.Format("{0}x{1}",
+                        previewImage.Source.Width, previewImage.Source.Height);
                 }
             }