diff --git a/OpenRa.Game/TileSheetBuilder.cs b/OpenRa.Game/TileSheetBuilder.cs
index 0c3c98b554..caf5893ac9 100644
--- a/OpenRa.Game/TileSheetBuilder.cs
+++ b/OpenRa.Game/TileSheetBuilder.cs
@@ -6,25 +6,48 @@ using System.Drawing;
 namespace OpenRa.Game
 {
 	// T is probably going to be BluntDirectX.Direct3D.Texture
-
-
 	public delegate T Provider<T>();
 
 	public class TileSheetBuilder<T>
 		where T : class
 	{
-		readonly Size pageSize;
+		readonly SizeF pageSize;
 		readonly Provider<T> pageProvider;
 
-		public TileSheetBuilder(Size pageSize, Provider<T> pageProvider)
+		public TileSheetBuilder(SizeF pageSize, Provider<T> pageProvider)
 		{
 			this.pageSize = pageSize;
 			this.pageProvider = pageProvider;
 		}
 
-		public SheetRectangle<T> AddImage(Size imageSize)
+		T current = null;
+		float x = 0, y = 0, rowHeight = 0;
+
+		public SheetRectangle<T> AddImage(SizeF imageSize)
 		{
-			throw new NotImplementedException();
+			if (imageSize.Width > pageSize.Width || imageSize.Height > pageSize.Height)
+				return null;
+
+			if (current == null)
+				current = pageProvider();
+
+			if (imageSize.Height > rowHeight || rowHeight == 0 || imageSize.Width + x > pageSize.Width)
+			{
+				y += rowHeight;
+				rowHeight = imageSize.Height;
+				x = 0;
+			}
+
+			if (y + imageSize.Height > pageSize.Height)
+			{
+				current = pageProvider();
+				x = y = rowHeight = 0;
+			}
+
+			SheetRectangle<T> rect = new SheetRectangle<T>(current, new PointF(x, y), imageSize);
+			x += imageSize.Width;
+
+			return rect;
 		}
 	}