This change should make the UI Icon Size setting dynamic, clearing all cached icons when the size changes (in the settings UI) so if they have a dynamic size the best is selected.

GreenshotPlugin/Core/PluginUtils.cs

@@ -25,6 +25,7 @@ using GreenshotPlugin.UnmanagedHelpers;
 using log4net;
 using Microsoft.Win32;
 using System;
+using System.Collections.Generic;
 using System.Drawing;
 using System.IO;
 using System.Windows.Forms;
@@ -37,6 +38,7 @@ namespace GreenshotPlugin.Core {
 		private static readonly ILog LOG = LogManager.GetLogger(typeof(PluginUtils));
 		private static CoreConfiguration conf = IniConfig.GetIniSection<CoreConfiguration>();
 		private const string PATH_KEY = @"SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\";
+		private static IDictionary<string, Image> exeIconCache = new Dictionary<string, Image>();
 
 		/// <summary>
 		/// Simple global property to get the Greenshot host
@@ -46,6 +48,21 @@ namespace GreenshotPlugin.Core {
 			set;
 		}
 
+		public static void ClearExeIconCache() {
+			List<Image> cachedImages = new List<Image>();
+			lock (exeIconCache) {
+				foreach (string key in exeIconCache.Keys) {
+					cachedImages.Add(exeIconCache[key]);
+				}
+				exeIconCache.Clear();
+			}
+			foreach (Image cachedImage in cachedImages) {
+				if (cachedImage != null) {
+					cachedImage.Dispose();
+				}
+			}
+		}
+
 		/// <summary>
 		/// Get the path of an executable
 		/// </summary>
@@ -70,6 +87,28 @@ namespace GreenshotPlugin.Core {
 			}
 			return null;
 		}
+		
+		/// <summary>
+		/// Get icon for executable, from the cache
+		/// </summary>
+		/// <param name="path">path to the exe or dll</param>
+		/// <param name="index">index of the icon</param>
+		/// <returns>Bitmap with the icon or null if something happended</returns>
+		public static Image GetCachedExeIcon(string path, int index) {
+			string cacheKey = string.Format("{0}:{1}", path, index);
+			Image returnValue;
+			if (!exeIconCache.TryGetValue(cacheKey, out returnValue)) {
+				lock (exeIconCache) {
+					if (!exeIconCache.TryGetValue(cacheKey, out returnValue)) {
+						returnValue = GetExeIcon(path, index);
+						if (returnValue != null) {
+							exeIconCache.Add(cacheKey, returnValue);
+						}
+					}
+				}
+			}
+			return returnValue;
+		}
 
 		/// <summary>
 		/// Get icon for executable
@@ -77,7 +116,7 @@ namespace GreenshotPlugin.Core {
 		/// <param name="path">path to the exe or dll</param>
 		/// <param name="index">index of the icon</param>
 		/// <returns>Bitmap with the icon or null if something happended</returns>
-		public static Bitmap GetExeIcon(string path, int index) {
+		private static Bitmap GetExeIcon(string path, int index) {
 			if (!File.Exists(path)) {
 				return null;
 			}

GreenshotPlugin/Core/WindowsHelper.cs

@@ -170,7 +170,6 @@ namespace GreenshotPlugin.Core  {
 		private static Dictionary<string, List<string>> classnameTree = new Dictionary<string, List<string>>();
 		private static CoreConfiguration conf = IniConfig.GetIniSection<CoreConfiguration>();
 		private static List<IntPtr> ignoreHandles = new List<IntPtr>();
-		private static Dictionary<string, Image> iconCache = new Dictionary<string, Image>();
 		private static List<string> excludeProcessesFromFreeze = new List<string>();
 		private static IAppVisibility appVisibility = null;
 		
@@ -204,7 +203,6 @@ namespace GreenshotPlugin.Core  {
 			}
 		}
 		
-		
 		public bool isGutter {
 			get {
 				return METRO_GUTTER_CLASS.Equals(ClassName);
@@ -307,17 +305,7 @@ namespace GreenshotPlugin.Core  {
 					return null;
 				}
 				try {
-					string filename = ProcessPath;
-					if (!iconCache.ContainsKey(filename)) {
-						Image icon = null;
-						using (Icon appIcon = Shell32.ExtractAssociatedIcon(filename)) {
-							if (appIcon != null) {
-								icon = appIcon.ToBitmap();
-							}
-						}
-						iconCache.Add(filename, icon);
-					}
-					return iconCache[filename];
+					return PluginUtils.GetCachedExeIcon(ProcessPath, 0);
 				} catch (Exception ex) {
 					LOG.WarnFormat("Couldn't get icon for window {0} due to: {1}", Text, ex.Message);
 					LOG.Warn(ex);