Use static images and converters.

Author: comintern

Rubberduck.Core/UI/AddRemoveReferences/ReferenceStatusImageSourceConverter.cs

@@ -10,7 +10,7 @@ namespace Rubberduck.UI.AddRemoveReferences
 {
     public class ReferenceStatusImageSourceConverter : ImageSourceConverter
     {
-        private readonly IDictionary<ReferenceStatus, ImageSource> _icons =
+        private static readonly IDictionary<ReferenceStatus, ImageSource> Icons =
             new Dictionary<ReferenceStatus, ImageSource>
             {
                 { ReferenceStatus.None, null },
@@ -29,8 +29,7 @@ public class ReferenceStatusImageSourceConverter : ImageSourceConverter
 
         public override object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            if (value == null || value.GetType() != typeof(ReferenceStatus)) { return null; }
-            return _icons[(ReferenceStatus)value];
+            return !(value is ReferenceStatus) ? null : Icons[(ReferenceStatus)value];
         }
     }
 }

Rubberduck.Core/UI/Converters/ImageSourceConverter.cs

@@ -13,12 +13,14 @@ public abstract class ImageSourceConverter : IValueConverter
         protected static ImageSource ToImageSource(Image source)
         {
             var ms = new MemoryStream();
+
             ((Bitmap)source).Save(ms, System.Drawing.Imaging.ImageFormat.Png);
             var image = new BitmapImage();
             image.BeginInit();
             ms.Seek(0, SeekOrigin.Begin);
             image.StreamSource = ms;
             image.EndInit();
+            image.Freeze();
 
             return image;
         }

Rubberduck.Core/UI/Inspections/InspectionImageSourceConverter.cs

@@ -7,22 +7,21 @@ namespace Rubberduck.UI.Inspections
 {
     public class InspectionImageSourceConverter : IValueConverter
     {
+        private static readonly InspectionSeverityImageSourceConverter SeverityConverter = new InspectionSeverityImageSourceConverter();
+
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            var inspection = value as IInspection;
-            if (inspection == null )
+            if (!(value is IInspection inspection))
             {
                 return null;
             }
 
-            var converter = new InspectionSeverityImageSourceConverter();
-            return converter.Convert(inspection.Severity, targetType, parameter, culture);
+            return SeverityConverter.Convert(inspection.Severity, targetType, parameter, culture);
         }
 
         public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            var converter = new InspectionSeverityImageSourceConverter();
-            return converter.ConvertBack(value, targetType, parameter, culture);
+            return SeverityConverter.ConvertBack(value, targetType, parameter, culture);
         }
     }
 }

Rubberduck.Core/UI/Inspections/InspectionSeverityImageSourceConverter.cs

@@ -1,18 +1,15 @@
 using System;
 using System.Collections.Generic;
-using System.Drawing;
 using System.Globalization;
-using System.IO;
 using System.Linq;
-using System.Windows.Data;
 using System.Windows.Media;
-using System.Windows.Media.Imaging;
 using Rubberduck.Parsing.Inspections;
 using Rubberduck.Resources.Inspections;
+using ImageSourceConverter = Rubberduck.UI.Converters.ImageSourceConverter;
 
 namespace Rubberduck.UI.Inspections
 {
-    public class InspectionSeverityImageSourceConverter : IValueConverter
+    public class InspectionSeverityImageSourceConverter : ImageSourceConverter
     {
         private static readonly IDictionary<CodeInspectionSeverity,ImageSource> Icons = 
             new Dictionary<CodeInspectionSeverity, ImageSource>
@@ -24,33 +21,14 @@ public class InspectionSeverityImageSourceConverter : IValueConverter
                 { CodeInspectionSeverity.Error, ToImageSource(InspectionsUI.cross_circle) },
             };
 
-        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        public override object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            if (value.GetType() != typeof(CodeInspectionSeverity))
-            {
-                throw new ArgumentException("value must be a CodeInspectionSeverity");
-            }
-
-            var severity = (CodeInspectionSeverity)value;
-            return Icons[severity];
+            return value is CodeInspectionSeverity severity ? Icons[severity] : null;
         }
 
-        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        public override object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
         {
             return Icons.First(f => Equals(f.Value, value)).Key;
         }
-
-        private static ImageSource ToImageSource(Image source)
-        {
-            var ms = new MemoryStream();
-            ((Bitmap)source).Save(ms, System.Drawing.Imaging.ImageFormat.Png);
-            var image = new BitmapImage();
-            image.BeginInit();
-            ms.Seek(0, SeekOrigin.Begin);
-            image.StreamSource = ms;
-            image.EndInit();
-
-            return image;
-        }
     }
 }