Added cache clear button, added cache size estimation

src/Helpers/ImageHelper.cs

@@ -53,4 +53,66 @@ public static class ImageHelper
             Thread.Sleep(10);
         }
     }
+
+    public static long GetImageCacheSize()
+    {
+        long size = 0;
+        int stringOverhead = GetStringOverhead();
+        int arrayOverhead = GetArrayOverhead();
+        foreach (var kvOuter in ImageCache)
+        {
+            foreach (var kvInner in kvOuter.Value)
+            {
+                size += System.Text.ASCIIEncoding.Unicode.GetByteCount(kvInner.Key);
+                size += stringOverhead;
+
+                // byte[] size
+                if (kvInner.Value != null)
+                    size += kvInner.Value.Length + arrayOverhead;
+            }
+        }
+        return size;
+    }
+
+    public static string ToHumanReadableSize(long bytes)
+    {
+        string[] sizes = ["B", "KB", "MB", "GB", "TB", "PB"];
+        double len = bytes;
+        int order = 0;
+
+        while (len >= 1024 && order < sizes.Length - 1)
+        {
+            order++;
+            len /= 1024;
+        }
+
+        return $"{len:0.##} {sizes[order]}";
+    }
+
+    private static int GetStringOverhead()
+    {
+        // Object header size
+        int header = IntPtr.Size == 8 ? 16 : 8; // 16 bytes on x64, 8 on x86
+
+        int size =
+            header +
+            sizeof(int) +                // string length field
+            sizeof(char);                // null terminator
+
+        return size;
+    }
+
+    private static int GetArrayOverhead()
+    {
+        // On x64 object header = 16 bytes; on x86 = 8 bytes
+        int header = IntPtr.Size == 8 ? 16 : 8;
+
+        // Array length field = 4 bytes
+        int lengthField = sizeof(int);
+
+        // Padding on x64 to align the elements (so the first element is aligned)
+        int padding = IntPtr.Size == 8 ? 4 : 0;
+
+        return header + lengthField + padding;
+    }
 }