diff --git a/rtiow/Cargo.lock b/rtiow/Cargo.lock
index 9557781..b8d6e99 100644
--- a/rtiow/Cargo.lock
+++ b/rtiow/Cargo.lock
@@ -1,8 +1,31 @@
+[[package]]
+name = "adler32"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "arrayvec"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "byteorder"
+version = "1.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "cfg-if"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "cloudabi"
 version = "0.0.3"
@@ -11,6 +34,56 @@ dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "color_quant"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-epoch 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memoffset 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "deflate"
+version = "0.7.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "adler32 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "either"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "fuchsia-zircon"
 version = "0.3.3"
@@ -25,11 +98,154 @@ name = "fuchsia-zircon-sys"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "gif"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "color_quant 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lzw 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "image"
+version = "0.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "gif 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "jpeg-decoder 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lzw 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-derive 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-iter 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-rational 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "png 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "scoped_threadpool 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "inflate"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "adler32 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "jpeg-decoder"
+version = "0.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rayon 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "lazy_static"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "version_check 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.43"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "lzw"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "memoffset"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "nodrop"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "num-derive"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.14.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-integer"
+version = "0.1.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-traits 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-iter"
+version = "0.1.37"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-rational"
+version = "0.1.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "num_cpus"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "png"
+version = "0.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "deflate 0.7.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "inflate 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-iter 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "quote"
+version = "0.6.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rand"
 version = "0.5.5"
@@ -47,13 +263,65 @@ name = "rand_core"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "rayon"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-deque 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rayon-core 1.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "crossbeam-deque 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.43 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rtiow"
 version = "0.1.0"
 dependencies = [
+ "image 0.19.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "scoped_threadpool"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "scopeguard"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "syn"
+version = "0.14.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "version_check"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "winapi"
 version = "0.3.5"
@@ -74,13 +342,47 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [metadata]
+"checksum adler32 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7e522997b529f05601e05166c07ed17789691f562762c7f3b987263d2dedee5c"
+"checksum arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)" = "a1e964f9e24d588183fcb43503abda40d288c8657dfc27311516ce2f05675aef"
 "checksum bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "228047a76f468627ca71776ecdebd732a3423081fcf5125585bcd7c49886ce12"
+"checksum byteorder 1.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "90492c5858dd7d2e78691cfb89f90d273a2800fc11d98f60786e5d87e2f83781"
+"checksum cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "0c4e7bb64a8ebb0d856483e1e682ea3422f883c5f5615a90d51a2c82fe87fdd3"
 "checksum cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
+"checksum color_quant 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0dbbb57365263e881e805dc77d94697c9118fd94d8da011240555aa7b23445bd"
+"checksum crossbeam-deque 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f739f8c5363aca78cfb059edf753d8f0d36908c348f3d8d1503f03d8b75d9cf3"
+"checksum crossbeam-epoch 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "927121f5407de9956180ff5e936fe3cf4324279280001cd56b669d28ee7e9150"
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+"checksum lzw 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7d947cbb889ed21c2a84be6ffbaebf5b4e0f4340638cba0444907e38b56be084"
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+"checksum nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "9a2228dca57108069a5262f2ed8bd2e82496d2e074a06d1ccc7ce1687b6ae0a2"
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+"checksum proc-macro2 0.4.19 (registry+https://github.com/rust-lang/crates.io-index)" = "ffe022fb8c8bd254524b0b3305906c1921fa37a84a644e29079a9e62200c3901"
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 "checksum rand 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e464cd887e869cddcae8792a4ee31d23c7edd516700695608f5b98c67ee0131c"
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+"checksum version_check 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "7716c242968ee87e5542f8021178248f267f295a5c4803beae8b8b7fd9bc6051"
 "checksum winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "773ef9dcc5f24b7d850d0ff101e542ff24c3b090a9768e03ff889fdef41f00fd"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/rtiow/Cargo.toml b/rtiow/Cargo.toml
index f87b3c2..84f0c2a 100644
--- a/rtiow/Cargo.toml
+++ b/rtiow/Cargo.toml
@@ -5,3 +5,4 @@ authors = ["Bill Thiede <rust@xinu.tv>"]
 
 [dependencies]
 rand = "0.5.5"
+image = "0.19.0"
diff --git a/rtiow/src/bin/tracer.rs b/rtiow/src/bin/tracer.rs
index 2fd39f0..b834b7f 100644
--- a/rtiow/src/bin/tracer.rs
+++ b/rtiow/src/bin/tracer.rs
@@ -1,8 +1,10 @@
+extern crate image;
 extern crate rand;
 extern crate rtiow;
 
 use std::time::Instant;
 
+use image::RgbImage;
 use rand::Rng;
 
 use rtiow::camera::Camera;
@@ -105,9 +107,11 @@ fn random_scene() -> Vec<Box<Hit>> {
 fn main() -> Result<(), std::io::Error> {
     let start = Instant::now();
     let mut rng = rand::thread_rng();
-    let nx = 1200;
-    let ny = 800;
-    let ns = 100;
+    // Set to 1 to do full res.
+    let dev_factor = 4;
+    let nx = 1200 / dev_factor;
+    let ny = 800 / dev_factor;
+    let ns = 100 / dev_factor;
     let (cam, world) = if BOOK_COVER {
         let lookfrom = Vec3::new(13., 2., 3.);
         let lookat = Vec3::new(0., 0., 0.);
@@ -167,8 +171,9 @@ fn main() -> Result<(), std::io::Error> {
         ]);
         (cam, world)
     };
-    println!("P3\n{} {}\n255", nx, ny);
-    for j in (0..ny).rev() {
+
+    let mut img = RgbImage::new(nx, ny);
+    for j in 0..ny {
         for i in 0..nx {
             let mut col: Vec3 = Default::default();
             for _ in 0..ns {
@@ -181,10 +186,11 @@ fn main() -> Result<(), std::io::Error> {
             // Gamma correct, use gamma 2 correction, which is 1/gamma where gamma=2 which is 1/2
             // or sqrt.
             col = Vec3::new(col[0].sqrt(), col[1].sqrt(), col[2].sqrt());
-            let ir = (255.99 * col[0]) as u32;
-            let ig = (255.99 * col[1]) as u32;
-            let ib = (255.99 * col[2]) as u32;
-            println!("{} {} {}", ir, ig, ib);
+            let ir = (255.99 * col[0]) as u8;
+            let ig = (255.99 * col[1]) as u8;
+            let ib = (255.99 * col[2]) as u8;
+            // ny-j is to flip y-axis.
+            img.put_pixel(i, ny - j - 1, image::Rgb([ir, ig, ib]));
         }
     }
     let runtime = start.elapsed();
@@ -193,5 +199,10 @@ fn main() -> Result<(), std::io::Error> {
         runtime.as_secs(),
         runtime.subsec_millis()
     );
+
+    let path = "/tmp/test.png";
+    // Write the contents of this image to the Writer in PNG format.
+    img.save(path).unwrap();
+    eprintln!("Saved {}", path);
     Ok(())
 }