diff --git a/src/components/main/constellation.rs b/src/components/main/constellation.rs
index 761abfb6164..1ec2a56e554 100644
--- a/src/components/main/constellation.rs
+++ b/src/components/main/constellation.rs
@@ -274,7 +274,7 @@ impl Constellation {
                 pending_frames: ~[],
                 pending_sizes: HashMap::new(),
                 profiler_chan: profiler_chan,
-                window_size: Size2D(500u, 500u),
+                window_size: Size2D(800u, 600u),
                 opts: opts_clone,
             };
             constellation.run();
diff --git a/src/components/main/servo.rc b/src/components/main/servo.rc
index b92f29893fc..8b717f181f9 100755
--- a/src/components/main/servo.rc
+++ b/src/components/main/servo.rc
@@ -50,7 +50,7 @@ use servo_msg::constellation_msg::InitLoadUrlMsg;
 use gfx::opts;
 
 #[cfg(not(test))]
-use servo_net::image_cache_task::ImageCacheTask;
+use servo_net::image_cache_task::{ImageCacheTask, SyncImageCacheTask};
 #[cfg(not(test))]
 use servo_net::resource_task::ResourceTask;
 #[cfg(not(test))]
@@ -149,7 +149,14 @@ fn run(opts: Opts) {
         let opts = &opts_clone;
         // Create a Servo instance.
         let resource_task = ResourceTask();
-        let image_cache_task = ImageCacheTask(resource_task.clone());
+        // If we are emitting an output file, then we need to block on
+        // image load or we risk emitting an output file missing the
+        // image.
+        let image_cache_task = if opts.output_file.is_some() {
+                SyncImageCacheTask(resource_task.clone())
+            } else {
+                ImageCacheTask(resource_task.clone())
+            };
         let constellation_chan = Constellation::start(compositor_chan,
                                                       opts,
                                                       resource_task,
diff --git a/src/support/png/rust-png b/src/support/png/rust-png
index 7a53b3042df..179900c871c 160000
--- a/src/support/png/rust-png
+++ b/src/support/png/rust-png
@@ -1 +1 @@
-Subproject commit 7a53b3042df5f483967b8bba283806d5f620954a
+Subproject commit 179900c871c2416824438cfce7fda737e9cba034