diff --git a/src/micropolisj/build_tool/MakeTiles.java b/src/micropolisj/build_tool/MakeTiles.java
index e856045..c30feb4 100644
--- a/src/micropolisj/build_tool/MakeTiles.java
+++ b/src/micropolisj/build_tool/MakeTiles.java
@@ -18,7 +18,6 @@ import static micropolisj.XML_Helper.*;
 public class MakeTiles
 {
 	static HashMap<String,String> tileData = new HashMap<String,String>();
-	static HashMap<String,SourceImage> loadedImages = new HashMap<String,SourceImage>();
 
 	static final Charset UTF8 = Charset.forName("UTF-8");
 	static int SKIP_TILES = 0;
@@ -431,6 +430,30 @@ public class MakeTiles
 		}
 	}
 
+	static class MyLoaderContext implements LoaderContext
+	{
+		HashMap<String,SourceImage> loadedImages = new HashMap<String,SourceImage>();
+
+		//implements LoaderContext
+		public SourceImage getDefaultImage()
+		{
+			throw new UnsupportedOperationException();
+		}
+
+		//implements LoaderContext
+		public SourceImage getImage(String fileName)
+			throws IOException
+		{
+			if (!loadedImages.containsKey(fileName)) {
+				loadedImages.put(fileName,
+					loadImageNoCache(fileName));
+			}
+
+			return loadedImages.get(fileName);
+		}
+	}
+	static MyLoaderContext loaderContext = new MyLoaderContext();
+
 	static TileImage loadImage(String fileName)
 		throws IOException
 	{
@@ -439,12 +462,7 @@ public class MakeTiles
 			return loadImageXml(xmlFile);
 		}
 
-		if (!loadedImages.containsKey(fileName)) {
-			loadedImages.put(fileName,
-				loadImageNoCache(fileName));
-		}
-
-		return loadedImages.get(fileName);
+		return loaderContext.getImage(fileName);
 	}
 
 	static SourceImage loadImageReal(File pngFile, int basisSize)
diff --git a/src/micropolisj/graphics/TileImage.java b/src/micropolisj/graphics/TileImage.java
index 0bff983..40e5b3e 100644
--- a/src/micropolisj/graphics/TileImage.java
+++ b/src/micropolisj/graphics/TileImage.java
@@ -2,6 +2,7 @@ package micropolisj.graphics;
 
 import java.awt.*;
 import java.awt.image.BufferedImage;
+import java.io.IOException;
 import java.util.*;
 import javax.xml.stream.*;
 
@@ -125,20 +126,27 @@ public abstract class TileImage
 
 	public interface LoaderContext
 	{
-		SourceImage getDefaultImage();
-		SourceImage getImage(String name);
+		SourceImage getDefaultImage()
+			throws IOException;
+		SourceImage getImage(String name)
+			throws IOException;
 	}
 
 	static SimpleTileImage readSimpleImage(XMLStreamReader in, LoaderContext ctx)
 		throws XMLStreamException
 	{
 		SimpleTileImage img = new SimpleTileImage();
-		String srcImageName = in.getAttributeValue(null, "src");
-		if (srcImageName != null) {
-			img.srcImage = ctx.getImage(srcImageName);
+		try {
+			String srcImageName = in.getAttributeValue(null, "src");
+			if (srcImageName != null) {
+				img.srcImage = ctx.getImage(srcImageName);
+			}
+			else {
+				img.srcImage = ctx.getDefaultImage();
+			}
 		}
-		else {
-			img.srcImage = ctx.getDefaultImage();
+		catch (IOException e) {
+			throw new XMLStreamException("image source not found", e);
 		}
 		String tmp = in.getAttributeValue(null, "offsetY");
 		img.offsetY = tmp != null ? Integer.parseInt(tmp) : 0;