In addition to registering a registerByteArrayHttpMessageConverter, you may want to use a ResponseEntity instead of @ResponseBody. The following code works for me :

@RequestMapping("/photo2")
public ResponseEntity<byte[]> testphoto() throws IOException {
    InputStream in = servletContext.getResourceAsStream("/images/no_image.jpg");

    final HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.IMAGE_PNG);

    return new ResponseEntity<byte[]>(IOUtils.toByteArray(in), headers, HttpStatus.CREATED);
}

In your application context declare a AnnotationMethodHandlerAdapter and registerByteArrayHttpMessageConverter:

<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
  <property name="messageConverters">
    <util:list>
      <bean id="byteArrayMessageConverter" class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/>
    </util:list>
  </property>
</bean> 

also in the handler method set appropriate content type for your response.

By using Spring 3.1.x and 3.2.x, this is how you should do it:

The controller method:

@RequestMapping("/photo2")
public @ResponseBody byte[] testphoto() throws IOException {
    InputStream in = servletContext.getResourceAsStream("/images/no_image.jpg");
    return IOUtils.toByteArray(in);
}

And the mvc annotation in servlet-context.xml file:

<mvc:annotation-driven>
    <mvc:message-converters>
        <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter">
            <property name="supportedMediaTypes">
                <list>
                    <value>image/jpeg</value>
                    <value>image/png</value>
                </list>
            </property>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

if you are using Spring version of 3.1 or newer you can specify "produces" in @RequestMappingannotation. Example below works for me out of box. No need of register converter or anything else if you have web mvc enabled (@EnableWebMvc).

@ResponseBody
@RequestMapping("/photo2", method = RequestMethod.GET, produces = MediaType.IMAGE_JPEG_VALUE)
public byte[] testphoto() throws IOException {
    InputStream in = servletContext.getResourceAsStream("/images/no_image.jpg");
    return IOUtils.toByteArray(in);
}