diff --git a/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageFilter.java b/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageFilter.java
index 13cc37de..9a9f79ac 100755
--- a/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageFilter.java
+++ b/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageFilter.java
@@ -115,23 +115,25 @@ public abstract class ImageFilter extends GenericFilter {
                 imageResponse.setImage(image);
                 //System.out.println("Done.");
 
-                if (encode) {
-                    //System.out.println("Encoding image...");
-                    // Encode image to original response
-                    if (image != null) {
-                        // TODO: Be smarter than this...
-                        // TODO: Make sure ETag is same, if image content is the same...
-                        // Use ETag of original response (or derived from)
-                        // Use last modified of original response? Or keep original resource's, don't set at all? 
-                        // TODO: Why weak ETag?
-                        String etag = "W/\"" + Integer.toHexString(hashCode()) + "-" + Integer.toHexString(image.hashCode()) + "\"";
-                        // TODO: This breaks for wrapped instances, need to either unwrap or test for HttpSR...
-                        ((HttpServletResponse) pResponse).setHeader("ETag", etag);
-                        ((HttpServletResponse) pResponse).setDateHeader("Last-Modified", (System.currentTimeMillis() / 1000) * 1000);
-                        imageResponse.flush();
-                    }
-                    //System.out.println("Done encoding.");
+            }
+
+            if (encode) {
+                //System.out.println("Encoding image...");
+                // Encode image to original response
+                if (image != null) {
+                    // TODO: Be smarter than this...
+                    // TODO: Make sure ETag is same, if image content is the same...
+                    // Use ETag of original response (or derived from)
+                    // Use last modified of original response? Or keep original resource's, don't set at all?
+                    // TODO: Why weak ETag?
+                    String etag = "W/\"" + Integer.toHexString(hashCode()) + "-" + Integer.toHexString(image.hashCode()) + "\"";
+                    // TODO: This breaks for wrapped instances, need to either unwrap or test for HttpSR...
+                    ((HttpServletResponse) pResponse).setHeader("ETag", etag);
+                    ((HttpServletResponse) pResponse).setDateHeader("Last-Modified", (System.currentTimeMillis() / 1000) * 1000);
                 }
+
+                imageResponse.flush();
+                //System.out.println("Done encoding.");
             }
         }
         //System.out.println("Filtering done.");
diff --git a/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageServletResponseImpl.java b/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageServletResponseImpl.java
index a2347d89..60f75370 100755
--- a/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageServletResponseImpl.java
+++ b/servlet/src/main/java/com/twelvemonkeys/servlet/image/ImageServletResponseImpl.java
@@ -242,9 +242,13 @@ class ImageServletResponseImpl extends HttpServletResponseWrapper implements Ima
         }
         else {
             super.setContentType(originalContentType);
+
             ServletOutputStream out = super.getOutputStream();
+
             try {
-                bufferedOut.writeTo(out);
+                if (bufferedOut != null) {
+                    bufferedOut.writeTo(out);
+                }
             }
             finally {
                 out.flush();
diff --git a/servlet/src/test/java/com/twelvemonkeys/servlet/image/ImageFilterTestCase.java b/servlet/src/test/java/com/twelvemonkeys/servlet/image/ImageFilterTestCase.java
new file mode 100644
index 00000000..c9d18d35
--- /dev/null
+++ b/servlet/src/test/java/com/twelvemonkeys/servlet/image/ImageFilterTestCase.java
@@ -0,0 +1,351 @@
+/*
+ * Copyright (c) 2011, Harald Kuhr
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name "TwelveMonkeys" nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.twelvemonkeys.servlet.image;
+
+import com.twelvemonkeys.io.FileUtil;
+import com.twelvemonkeys.servlet.OutputStreamAdapter;
+import com.twelvemonkeys.util.StringTokenIterator;
+import org.junit.Test;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+
+import javax.servlet.*;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.awt.image.RenderedImage;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+/**
+ * ImageFilterTestCase
+ *
+ * @author <a href="mailto:harald.kuhr@gmail.com">Harald Kuhr</a>
+ * @author last modified by $Author: haraldk$
+ * @version $Id: ImageFilterTestCase.java,v 1.0 07.04.11 14.14 haraldk Exp$
+ */
+public class ImageFilterTestCase {
+
+    @Test
+    public void passThroughIfNotTrigger() throws ServletException, IOException {
+        // Filter init & setup
+        ServletContext context = mock(ServletContext.class);
+
+        FilterConfig filterConfig = mock(FilterConfig.class);
+        when(filterConfig.getFilterName()).thenReturn("dummy");
+        when(filterConfig.getServletContext()).thenReturn(context);
+        when(filterConfig.getInitParameterNames()).thenReturn(new StringTokenIterator("foo, bar"));
+
+        DummyFilter filter = new DummyFilter() {
+            @Override
+            protected boolean trigger(ServletRequest pRequest) {
+                return false;
+            }
+        };
+        filter.init(filterConfig);
+
+        // Request/response setup
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        HttpServletResponse response = mock(HttpServletResponse.class);
+
+        FilterChain chain = mock(FilterChain.class);
+
+        // Execute
+        filter.doFilter(request, response, chain);
+
+        // Verifications
+        verify(chain).doFilter(request, response);
+    }
+
+    @Test
+    public void normalFilter() throws ServletException, IOException {
+        // Filter init & setup
+        ServletContext context = mock(ServletContext.class);
+
+        FilterConfig filterConfig = mock(FilterConfig.class);
+        when(filterConfig.getFilterName()).thenReturn("dummy");
+        when(filterConfig.getServletContext()).thenReturn(context);
+        when(filterConfig.getInitParameterNames()).thenReturn(new StringTokenIterator("foo, bar"));
+
+        DummyFilter filter = new DummyFilter();
+        filter.init(filterConfig);
+
+        // Request/response setup
+        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        ServletOutputStream out = spy(new OutputStreamAdapter(stream));
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(out);
+
+        FilterChain chain = mock(FilterChain.class);
+        doAnswer(new Answer<Void>() {
+            public Void answer(InvocationOnMock invocation) throws Throwable {
+                HttpServletResponse response = (HttpServletResponse) invocation.getArguments()[1];
+
+                response.setContentType("image/png");
+                response.setContentLength(104417);
+                InputStream stream = getClass().getResourceAsStream("/com/twelvemonkeys/servlet/image/12monkeys-splash.png");
+                assertNotNull("Missing test resource", stream);
+                FileUtil.copy(stream, response.getOutputStream());
+
+                return null;
+            }
+        }).when(chain).doFilter(any(ServletRequest.class), any(ServletResponse.class));
+
+        // Execute
+        filter.doFilter(request, response, chain);
+
+        // Verifications
+        int length = stream.size();
+
+        verify(chain).doFilter(any(ServletRequest.class), any(ServletResponse.class));
+        verify(response).setContentType("image/png");
+        verify(response, atMost(1)).setContentLength(length); // setContentLength not implemented, avoid future bugs
+        verify(out, atLeastOnce()).flush();
+
+        // Extra verification here, until we come up with something better
+        assertTrue(
+                String.format("Unlikely length for PNG (please run manual check): %s bytes, expected about 85000 bytes", length),
+                length >= 60000 && length <= 120000
+        );
+    }
+
+    @Test
+    public void filterNoContent() throws ServletException, IOException {
+        // Filter init & setup
+        ServletContext context = mock(ServletContext.class);
+
+        FilterConfig filterConfig = mock(FilterConfig.class);
+        when(filterConfig.getFilterName()).thenReturn("dummy");
+        when(filterConfig.getServletContext()).thenReturn(context);
+        when(filterConfig.getInitParameterNames()).thenReturn(new StringTokenIterator("foo, bar"));
+
+        DummyFilter filter = new DummyFilter();
+        filter.init(filterConfig);
+
+        // Request/response setup
+        ServletOutputStream out = mock(ServletOutputStream.class);
+
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(out);
+
+        FilterChain chain = mock(FilterChain.class);
+        doAnswer(new Answer<Void>() {
+            public Void answer(InvocationOnMock invocation) throws Throwable {
+                HttpServletResponse response = (HttpServletResponse) invocation.getArguments()[1];
+
+                response.setContentType("image/x-imaginary");
+
+                return null;
+            }
+        }).when(chain).doFilter(any(ServletRequest.class), any(ServletResponse.class));
+
+        // Execute
+        filter.doFilter(request, response, chain);
+
+        // Verifications
+        verify(chain).doFilter(any(ServletRequest.class), any(ServletResponse.class));
+        verify(response).setContentType("image/x-imaginary");
+        verify(out, atLeastOnce()).flush();
+    }
+
+    @Test
+    public void triggerWhenTriggerParamsNull() throws ServletException {
+        // Filter init & setup
+        ServletContext context = mock(ServletContext.class);
+
+        FilterConfig filterConfig = mock(FilterConfig.class);
+        when(filterConfig.getFilterName()).thenReturn("dummy");
+        when(filterConfig.getServletContext()).thenReturn(context);
+        when(filterConfig.getInitParameterNames()).thenReturn(new StringTokenIterator("foo, bar"));
+
+        DummyFilter filter = new DummyFilter();
+
+        filter.init(filterConfig);
+
+        // Execute/Verifications
+        assertTrue(filter.trigger(mock(HttpServletRequest.class)));
+    }
+
+    @Test
+    public void triggerWithTriggerParams() throws ServletException {
+        // Filter init & setup
+        ServletContext context = mock(ServletContext.class);
+
+        FilterConfig filterConfig = mock(FilterConfig.class);
+        when(filterConfig.getFilterName()).thenReturn("dummy");
+        when(filterConfig.getServletContext()).thenReturn(context);
+        when(filterConfig.getInitParameterNames()).thenReturn(new StringTokenIterator("triggerParams"));
+        when(filterConfig.getInitParameter("triggerParams")).thenReturn("foo");
+
+        DummyFilter filter = new DummyFilter();
+
+        filter.init(filterConfig);
+
+        // Request/response setup
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        when(request.getParameter("foo")).thenReturn("doit");
+
+
+        // Execute/Verifications
+        assertTrue(filter.trigger(request));
+    }
+
+    @Test
+    public void dontTriggerWithoutTriggerParams() throws ServletException {
+        // Filter init & setup
+        ServletContext context = mock(ServletContext.class);
+
+        FilterConfig filterConfig = mock(FilterConfig.class);
+        when(filterConfig.getFilterName()).thenReturn("dummy");
+        when(filterConfig.getServletContext()).thenReturn(context);
+        when(filterConfig.getInitParameterNames()).thenReturn(new StringTokenIterator("triggerParams"));
+        when(filterConfig.getInitParameter("triggerParams")).thenReturn("foo");
+
+        DummyFilter filter = new DummyFilter();
+
+        filter.init(filterConfig);
+
+        // Request/response setup
+        HttpServletRequest request = mock(HttpServletRequest.class);
+
+
+        // Execute/Verifications
+        assertFalse(filter.trigger(request));
+    }
+
+    @Test
+    public void testChaining() throws ServletException, IOException {
+        // Filter init & setup
+        ServletContext context = mock(ServletContext.class);
+
+        FilterConfig fooConfig = mock(FilterConfig.class);
+        when(fooConfig.getFilterName()).thenReturn("foo");
+        when(fooConfig.getServletContext()).thenReturn(context);
+        when(fooConfig.getInitParameterNames()).thenReturn(new StringTokenIterator(""));
+
+        final AtomicReference<BufferedImage> imageRef = new AtomicReference<BufferedImage>();
+        final AtomicReference<ImageServletResponse> responseRef = new AtomicReference<ImageServletResponse>();
+
+        DummyFilter fooFilter = new DummyFilter() {
+            @Override
+            protected RenderedImage doFilter(BufferedImage image, ServletRequest request, ImageServletResponse response) throws IOException {
+                // NOTE: Post-filtering, this method is run after barFilter.doFilter
+                assertEquals(imageRef.get(), image);
+                assertEquals(responseRef.get(), response);
+
+                return image;
+            }
+        };
+        fooFilter.init(fooConfig);
+
+        FilterConfig barConfig = mock(FilterConfig.class);
+        when(barConfig.getFilterName()).thenReturn("bar");
+        when(barConfig.getServletContext()).thenReturn(context);
+        when(barConfig.getInitParameterNames()).thenReturn(new StringTokenIterator(""));
+
+        final DummyFilter barFilter = new DummyFilter() {
+            @Override
+            protected RenderedImage doFilter(BufferedImage image, ServletRequest request, ImageServletResponse response) throws IOException {
+                // NOTE: Post-filtering, this method is run before fooFilter.doFilter
+                Graphics2D graphics = image.createGraphics();
+                try {
+                    graphics.drawRect(10, 10, 100, 100);
+                }
+                finally {
+                    graphics.dispose();
+                }
+
+                // Store references for later, make sure this is first and only set.
+                assertTrue(imageRef.compareAndSet(null, image));
+                assertTrue(responseRef.compareAndSet(null, response));
+
+                return image;
+            }
+        };
+        barFilter.init(barConfig);
+
+        // Request/response setup
+        ServletOutputStream out = mock(ServletOutputStream.class);
+        HttpServletRequest request = mock(HttpServletRequest.class);
+        HttpServletResponse response = mock(HttpServletResponse.class);
+        when(response.getOutputStream()).thenReturn(out);
+
+        FilterChain chain = mock(FilterChain.class);
+        final AtomicBoolean first = new AtomicBoolean(false);
+        doAnswer(new Answer<Void>() {
+            public Void answer(InvocationOnMock invocation) throws Throwable {
+                HttpServletRequest request = (HttpServletRequest) invocation.getArguments()[0];
+                HttpServletResponse response = (HttpServletResponse) invocation.getArguments()[1];
+
+                // Fake chaining here..
+                if (first.compareAndSet(false, true)) {
+                    barFilter.doFilter(request, response, (FilterChain) invocation.getMock());
+                    return null;
+                }
+
+                // Otherwise, fake servlet/file response
+                response.setContentType("image/gif");
+                InputStream stream = getClass().getResourceAsStream("/com/twelvemonkeys/servlet/image/tux.gif");
+                assertNotNull("Missing test resource", stream);
+                FileUtil.copy(stream, response.getOutputStream());
+
+                return null;
+            }
+        }).when(chain).doFilter(any(ServletRequest.class), any(ServletResponse.class));
+
+        // Execute
+        fooFilter.doFilter(request, response, chain);
+
+        // Verifications
+        verify(chain, times(2)).doFilter(any(ServletRequest.class), any(ImageServletResponse.class));
+        verify(response).setContentType("image/gif");
+        verify(out, atLeastOnce()).flush();
+
+        // NOTE:
+        // We verify that the image is the same in both ImageFilter implementations, to make sure the image is only
+        // decoded once, then encoded once
+    }
+
+    private static class DummyFilter extends ImageFilter {
+        @Override
+        protected RenderedImage doFilter(BufferedImage image, ServletRequest request, ImageServletResponse response) throws IOException {
+            return image;
+        }
+    }
+}