diff --git a/cz/src/common.rs b/cz/src/common.rs
index 5ec8665..7cbe9be 100644
--- a/cz/src/common.rs
+++ b/cz/src/common.rs
@@ -58,7 +58,7 @@ impl TryFrom<u8> for CzVersion {
 }
 
 pub trait CzHeader {
-    fn new<T: Seek + ReadBytesExt + Read>(bytes: &mut T) -> Result<Self, CzError>
+    fn from_bytes<T: Seek + ReadBytesExt + Read>(bytes: &mut T) -> Result<Self, CzError>
     where
         Self: Sized;
 
@@ -122,8 +122,29 @@ pub struct CommonHeader {
     unknown: u8,
 }
 
+impl CommonHeader {
+    pub fn new(
+        version: CzVersion,
+        width: u16,
+        height: u16,
+    ) -> Self {
+        Self {
+            version,
+            length: 15,
+            width,
+            height,
+            depth: 32,
+            unknown: 0
+        }
+    }
+
+    pub fn set_length(&mut self, length: u32) {
+        self.length = length
+    }
+}
+
 impl CzHeader for CommonHeader {
-    fn new<T: Seek + ReadBytesExt + Read>(bytes: &mut T) -> Result<Self, CzError>
+    fn from_bytes<T: Seek + ReadBytesExt + Read>(bytes: &mut T) -> Result<Self, CzError>
     where
         Self: Sized,
     {
@@ -243,7 +264,37 @@ pub struct ExtendedHeader {
 }
 
 impl ExtendedHeader {
-    pub fn new<T: Seek + ReadBytesExt + Read>(
+    pub fn new(
+        crop_width: u16,
+        crop_height: u16,
+        bounds_width: u16,
+        bounds_height: u16,
+    ) -> Self {
+        ExtendedHeader {
+            unknown_1: [0u8; 5],
+            crop_width,
+            crop_height,
+            bounds_width,
+            bounds_height,
+            offset_width: None,
+            offset_height: None,
+            unknown_2: None
+        }
+    }
+
+    pub fn with_offset(
+        mut self,
+        offset_width: u16,
+        offset_height: u16
+    ) -> Self {
+        self.offset_width = Some(offset_width);
+        self.offset_height = Some(offset_height);
+        self.unknown_2 = Some(0);
+
+        self
+    }
+
+    pub fn from_bytes<T: Seek + ReadBytesExt + Read>(
         input: &mut T,
         common_header: &CommonHeader
     ) -> Result<Self, CzError> {
diff --git a/cz/src/compression.rs b/cz/src/compression.rs
index b1ae0ed..01b4e3d 100644
--- a/cz/src/compression.rs
+++ b/cz/src/compression.rs
@@ -334,7 +334,7 @@ pub fn compress(
     let mut part_data;
 
     let mut offset = 0;
-    let mut count = 0;
+    let mut count;
     let mut last = Vec::new();
 
     let mut output_buf: Vec<u8> = vec![];
@@ -362,6 +362,13 @@ pub fn compress(
         output_info.chunk_count += 1;
     }
 
+    if output_info.chunk_count == 0 {
+        panic!("No chunks compressed!")
+    } else if output_info.chunk_count != 1 {
+        output_info.chunks[0].size_raw -= 1;
+        output_info.chunks[output_info.chunk_count - 1].size_raw += 1;
+    }
+
     output_info.total_size_compressed = output_buf.len() / 2;
 
     (output_buf, output_info)
diff --git a/cz/src/dynamic.rs b/cz/src/dynamic.rs
index eec5caa..6424aec 100644
--- a/cz/src/dynamic.rs
+++ b/cz/src/dynamic.rs
@@ -33,15 +33,53 @@ impl DynamicCz {
 
         Ok(())
     }
+
+    pub fn from_raw(
+        version: CzVersion,
+        width: u16,
+        height: u16,
+        bitmap: Vec<u8>,
+    ) -> Self {
+        let header_common = CommonHeader::new(
+            version,
+            width,
+            height
+        );
+
+        Self {
+            header_common,
+            header_extended: None,
+            palette: None,
+            bitmap,
+        }
+    }
+
+    pub fn with_header(mut self, header: CommonHeader) -> Self {
+        self.header_common = header;
+
+        self
+    }
+
+    pub fn with_extended_header(mut self, ext_header: ExtendedHeader) -> Self {
+        if ext_header.offset_width.is_none() {
+            self.header_common.set_length(28)
+        } else {
+            self.header_common.set_length(36)
+        }
+
+        self.header_extended = Some(ext_header);
+
+        self
+    }
 }
 
 impl DynamicCz {
     pub fn decode<T: Seek + ReadBytesExt + Read>(input: &mut T) -> Result<Self, CzError> {
         // Get the header common to all CZ images
-        let header_common = CommonHeader::new(input)?;
+        let header_common = CommonHeader::from_bytes(input)?;
         let mut header_extended = None;
         if header_common.length() > 15 && header_common.version() != CzVersion::CZ2 {
-            header_extended = Some(ExtendedHeader::new(input, &header_common)?);
+            header_extended = Some(ExtendedHeader::from_bytes(input, &header_common)?);
         }
         input.seek(SeekFrom::Start(header_common.length() as u64))?;
 
diff --git a/cz/src/formats/cz1.rs b/cz/src/formats/cz1.rs
index b52b44b..52a79f8 100644
--- a/cz/src/formats/cz1.rs
+++ b/cz/src/formats/cz1.rs
@@ -21,7 +21,7 @@ pub fn encode<T: WriteBytesExt + Write>(
     output: &mut T,
     bitmap: &[u8]
 ) -> Result<(), CzError> {
-    let (compressed_data, compressed_info) = compress(bitmap, 65277);
+    let (compressed_data, compressed_info) = compress(bitmap, 0xFEFD);
 
     dbg!(&compressed_info);
 
diff --git a/cz/src/formats/cz3.rs b/cz/src/formats/cz3.rs
index dea8f0f..5e0c0ab 100644
--- a/cz/src/formats/cz3.rs
+++ b/cz/src/formats/cz3.rs
@@ -24,7 +24,7 @@ pub fn encode<T: WriteBytesExt + Write, H: CzHeader>(
 ) -> Result<(), CzError> {
     let bitmap = diff_line(header, bitmap);
 
-    let (compressed_data, compressed_info) = compress(&bitmap, 65277);
+    let (compressed_data, compressed_info) = compress(&bitmap, 0xFEFD);
 
     compressed_info.write_into(output)?;
 
diff --git a/utils/src/main.rs b/utils/src/main.rs
index f47c938..04deefc 100644
--- a/utils/src/main.rs
+++ b/utils/src/main.rs
@@ -1,11 +1,23 @@
-use cz::dynamic::DynamicCz;
+use cz::{common::{CzVersion, ExtendedHeader}, dynamic::DynamicCz};
 
 fn main() {
-    let img = DynamicCz::open("font72.cz1").unwrap();
+    let mio = image::open("mio_inverted.png").unwrap();
+    let mio = mio.to_rgba8();
 
-    img.save_as_cz("test.cz1").unwrap();
-    img.save_as_png("test1.png").unwrap();
+    let cz_mio =
+        DynamicCz::from_raw(
+            CzVersion::CZ3,
+            mio.width() as u16,
+            mio.height() as u16,
+            mio.into_raw()
+        )
+        .with_extended_header(
+            ExtendedHeader::new(1280, 960, 1280, 960)
+        );
 
-    let img2 = DynamicCz::open("test.cz1").unwrap();
-    img2.save_as_png("test2.png").unwrap();
+    cz_mio.save_as_cz("test1.cz3").unwrap();
+
+    let img = DynamicCz::open("test1.cz3").unwrap();
+
+    img.save_as_png("test.png").unwrap();
 }