diff --git a/Cargo.lock b/Cargo.lock
index 8e9cce6..6e120c1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -45,16 +45,31 @@ dependencies = [
  "safemem 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "bit-vec"
+version = "0.6.1"
+source = "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 = "build_const"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "byteorder"
 version = "1.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "cc"
+version = "1.0.38"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "cfg-if"
 version = "0.1.6"
@@ -82,11 +97,43 @@ dependencies = [
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "cloudflare-zlib"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cloudflare-zlib-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "cloudflare-zlib-sys"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cc 1.0.38 (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 = "crc"
+version = "1.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "build_const 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "crc32fast"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.2.0"
@@ -146,6 +193,11 @@ dependencies = [
  "lzw 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "glob"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "image"
 version = "0.20.1"
@@ -163,6 +215,19 @@ dependencies = [
  "tiff 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "image"
+version = "0.21.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lzw 0.10.0 (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 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "png 0.14.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "inflate"
 version = "0.4.3"
@@ -171,6 +236,14 @@ dependencies = [
  "adler32 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "jpeg-decoder"
 version = "0.1.15"
@@ -200,6 +273,14 @@ name = "memoffset"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "miniz_oxide"
+version = "0.2.3"
+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 = "nodrop"
 version = "0.1.13"
@@ -255,6 +336,26 @@ dependencies = [
  "libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "oxipng"
+version = "2.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bit-vec 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cloudflare-zlib 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crc 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "image 0.21.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "miniz_oxide 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rayon 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rgb 0.8.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wild 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "zopfli 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "png"
 version = "0.12.0"
@@ -266,6 +367,28 @@ dependencies = [
  "num-iter 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "png"
+version = "0.14.1"
+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 0.7.19 (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 = "png"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crc32fast 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "deflate 0.7.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "inflate 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "0.4.24"
@@ -420,6 +543,11 @@ dependencies = [
  "redox_syscall 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rgb"
+version = "0.8.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "ron"
 version = "0.4.0"
@@ -471,6 +599,7 @@ dependencies = [
  "ron 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.80 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "twox-hash 1.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -480,11 +609,18 @@ version = "0.2.0"
 dependencies = [
  "clap 2.32.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "image 0.20.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "oxipng 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "png 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "ron 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.89 (registry+https://github.com/rust-lang/crates.io-index)",
  "sheep 0.2.1",
 ]
 
+[[package]]
+name = "smallvec"
+version = "0.6.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "strsim"
 version = "0.7.0"
@@ -537,6 +673,11 @@ dependencies = [
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "typed-arena"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "unicode-width"
 version = "0.1.5"
@@ -552,6 +693,14 @@ name = "vec_map"
 version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "wild"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.6"
@@ -571,6 +720,17 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "zopfli"
+version = "0.4.0"
+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 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crc 1.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "typed-arena 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
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 "checksum adler32 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7e522997b529f05601e05166c07ed17789691f562762c7f3b987263d2dedee5c"
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
@@ -578,12 +738,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9a7d5b8723950951411ee34d271d99dddcc2035a16ab25310ea2c8cfd4369652"
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 "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"
 "checksum crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2760899e32a1d58d5abb31129f8fae5de75220bc2176e77ff7c627ae45c918d9"
@@ -591,13 +758,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum either 1.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3be565ca5c557d7f59e7cfcf1844f9e3033650c929c6566f511e8005f205c1d0"
 "checksum fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
 "checksum gif 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "dd4bca55ac1f213920ce3527ccd62386f1f15fa3f1714aeee1cf93f2c416903f"
+"checksum glob 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
 "checksum image 0.20.1 (registry+https://github.com/rust-lang/crates.io-index)" = "44665b4395d1844c96e7dc8ed5754782a1cdfd9ef458a80bbe45702681450504"
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 "checksum inflate 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6f53b811ee8e2057ccf9643ca6b4277de90efaf5e61e55fd5254576926bb4245"
+"checksum itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5b8467d9c1cebe26feb08c640139247fac215782d35371ade9a2136ed6085358"
 "checksum jpeg-decoder 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "c8b7d43206b34b3f94ea9445174bda196e772049b9bddbc620c9d29b2d20110d"
 "checksum lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a374c89b9db55895453a74c1e38861d9deec0b01b405a82516e9d5de4820dea1"
 "checksum libc 0.2.44 (registry+https://github.com/rust-lang/crates.io-index)" = "10923947f84a519a45c8fefb7dd1b3e8c08747993381adee176d7a82b4195311"
 "checksum lzw 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7d947cbb889ed21c2a84be6ffbaebf5b4e0f4340638cba0444907e38b56be084"
 "checksum memoffset 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0f9dc261e2b62d7a622bf416ea3c5245cdd5d9a7fcc428c0d06804dfce1775b3"
+"checksum miniz_oxide 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "5f6d7b3dd914b70db7cef7ab9dc74339ffcadf4d033464a987237bb0b9418cd4"
 "checksum nodrop 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)" = "2f9667ddcc6cc8a43afc9b7917599d7216aa09c463919ea32c59ed6cac8bc945"
 "checksum num-derive 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "8af1847c907c2f04d7bfd572fb25bbb4385c637fe5be163cf2f8c5d778fe1e7d"
 "checksum num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)" = "e83d528d2677f0518c570baf2b7abdcf0cd2d248860b68507bdcb3e91d4c0cea"
@@ -605,7 +776,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum num-rational 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4e96f040177bb3da242b5b1ecf3f54b5d5af3efbbfb18608977a5d2767b22f10"
 "checksum num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0b3a5d7cc97d6d30d8b9bc8fa19bf45349ffe46241e8816f50f62f6d6aaabee1"
 "checksum num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c51a3322e4bca9d212ad9a158a02abc6934d005490c054a2778df73a70aa0a30"
+"checksum oxipng 2.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d67ce5cdb09fc0c53e328f2df0f6ebd2ec3582d2f1eaf4b1cdc9dfe991cd5020"
 "checksum png 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f54b9600d584d3b8a739e1662a595fab051329eff43f20e7d8cc22872962145b"
+"checksum png 0.14.1 (registry+https://github.com/rust-lang/crates.io-index)" = "63daf481fdd0defa2d1d2be15c674fbfa1b0fd71882c303a91f9a79b3252c359"
+"checksum png 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8422b27bb2c013dd97b9aef69e161ce262236f49aaf46a0489011c8ff0264602"
 "checksum proc-macro2 0.4.24 (registry+https://github.com/rust-lang/crates.io-index)" = "77619697826f31a02ae974457af0b29b723e5619e113e9397b8b82c6bd253f09"
 "checksum quote 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)" = "53fa22a1994bd0f9372d7a816207d8a2677ad0325b073f5c5332760f0fb62b5c"
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@@ -623,21 +797,26 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
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 "checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
+"checksum rgb 0.8.13 (registry+https://github.com/rust-lang/crates.io-index)" = "4f089652ca87f5a82a62935ec6172a534066c7b97be003cc8f702ee9a7a59c92"
 "checksum ron 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c48677d8a9247a4e0d1f3f9cb4b0a8e29167fdc3c04f383a5e669cd7a960ae0f"
 "checksum safemem 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8dca453248a96cb0749e36ccdfe2b0b4e54a61bfef89fb97ec621eb8e0a93dd9"
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diff --git a/sheep_cli/Cargo.toml b/sheep_cli/Cargo.toml
index 13678a3..3952620 100644
--- a/sheep_cli/Cargo.toml
+++ b/sheep_cli/Cargo.toml
@@ -21,6 +21,8 @@ sheep = { path = "../sheep", version = "0.2.1" }
 image = "0.20"
 clap = "2.32"
 ron = "0.4"
+oxipng = "2.2"
+png = "0.15"
 
 [[bin]]
 name = "sheep"
diff --git a/sheep_cli/src/main.rs b/sheep_cli/src/main.rs
index 7e7dd50..78d4f91 100644
--- a/sheep_cli/src/main.rs
+++ b/sheep_cli/src/main.rs
@@ -5,10 +5,10 @@ extern crate serde;
 extern crate sheep;
 
 use clap::{App, AppSettings, Arg, SubCommand};
-use image::RgbaImage;
 use serde::Serialize;
 use sheep::{
-    AmethystFormat, AmethystNamedFormat, InputSprite, MaxrectsOptions, MaxrectsPacker, SimplePacker,
+    AmethystFormat, AmethystNamedFormat, InputSprite, MaxrectsOptions, MaxrectsPacker,
+    SimplePacker, SpriteSheet,
 };
 use std::str::FromStr;
 use std::{fs::File, io::prelude::*};
@@ -79,6 +79,12 @@ fn main() {
                         .short("t")
                         .long("trim"),
                 )
+                .arg(
+                    Arg::with_name("compress")
+                        .help("Use png compression")
+                        .short("c")
+                        .long("compress"),
+                ),
         );
 
     let matches = app.get_matches();
@@ -142,12 +148,8 @@ fn main() {
                     format!("{}-{:02}", out, i)
                 };
 
-                let outbuf = RgbaImage::from_vec(
-                    sheet.dimensions.0,
-                    sheet.dimensions.1,
-                    sheet.bytes.clone(),
-                )
-                .expect("Failed to create image from spritesheet");
+                let compress = matches.is_present("compress");
+                write_image(&filename, sheet, compress);
 
                 let pretty = matches.is_present("pretty");
 
@@ -155,11 +157,11 @@ fn main() {
                     Some("amethyst_named") => {
                         let names = get_filenames(&input);
                         let meta = sheep::encode::<AmethystNamedFormat>(&sheet, names);
-                        write_files(&filename, outbuf, meta, pretty);
+                        write_meta(&filename, meta, pretty);
                     }
                     Some("amethyst") => {
                         let meta = sheep::encode::<AmethystFormat>(&sheet, ());
-                        write_files(&filename, outbuf, meta, pretty);
+                        write_meta(&filename, meta, pretty);
                     }
                     _ => panic!("Unknown format"),
                 };
@@ -208,11 +210,40 @@ fn load_images(input: &[String]) -> Vec<InputSprite> {
         .collect()
 }
 
-fn write_files<S: Serialize>(output_path: &str, outbuf: RgbaImage, meta: S, pretty: bool) {
-    outbuf
-        .save(format!("{}.png", output_path))
-        .expect("Failed to save image");
+fn write_image(output_path: &str, sheet: &SpriteSheet, compress: bool) {
+    let filename = format!("{}.png", output_path);
+
+    let mut png_bytes = Vec::<u8>::new();
+    {
+        let mut encoder = png::Encoder::new(&mut png_bytes, sheet.dimensions.0, sheet.dimensions.1);
+        encoder.set_color(png::ColorType::RGBA);
+        encoder.set_depth(png::BitDepth::Eight);
+        encoder.set_compression(png::Compression::Fast);
+        encoder.set_filter(png::FilterType::NoFilter);
+        let mut writer = encoder.write_header().expect("Failed to write png header");
+        writer
+            .write_image_data(&sheet.bytes)
+            .expect("Failed to write png data");
+    }
+    let png_bytes = if compress {
+        // you can read about presets in oxipng readme on github
+        // level 2 is sufficently fast on modern CPU's and
+        // provides 30-50% compression
+        // higher preset levels execute much (> 6x) slover and
+        // can only give about 10% additional compression
+        let options = oxipng::Options::from_preset(2);
+        oxipng::optimize_from_memory(png_bytes.as_slice(), &options)
+            .expect("Failed to compress png")
+    } else {
+        png_bytes
+    };
+
+    let mut file = File::create(filename).expect("Failed to create image file");
+    file.write_all(png_bytes.as_slice())
+        .expect("Failed to write image to file");
+}
 
+fn write_meta<S: Serialize>(output_path: &str, meta: S, pretty: bool) {
     let mut meta_file =
         File::create(format!("{}.ron", output_path)).expect("Failed to create meta file");