Create ImageCollectionExtension

-Added basic Insert method for ImageCollections

PckStudio.Core/Extensions/ImageCollectionExtensions.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace PckStudio.Core.Extensions
+{
+    public static class ImageCollectionExtensions
+    {
+        public static void Insert(this ImageList.ImageCollection _, int index, string key, Image image)
+        {
+            var images = new List<Image>();
+            var keys = new List<string>();
+
+            for (int i = 0; i < _.Count; i++)
+            {
+                keys.Add(_.Keys[i]);
+                images.Add(_[i]);
+            }
+
+            images.Insert(index, image);
+            keys.Insert(index, key);
+
+            _.Clear();
+
+            for (int i = 0; i < images.Count; i++)
+            {
+                _.Add(keys[i], images[i]);
+            }
+        }
+    }
+}