diff --git a/lib/binary_kata.ex b/lib/binary_kata.ex
index eb75fef..1c3314a 100644
--- a/lib/binary_kata.ex
+++ b/lib/binary_kata.ex
@@ -1,20 +1,21 @@
 defmodule BinaryKata do
-
   @doc """
   Should return `true` when given parameter start with UTF8 Byte-Order-Mark, otherwise `false`.
   @see https://en.wikipedia.org/wiki/Byte_order_mark
   """
-  def has_utf8_bom?(_), do: raise "TODO: Implement me!"
+  def has_utf8_bom?(<< 0xEF, 0xBB, 0xBF, _ :: binary >>), do: true
+  def has_utf8_bom?(_), do: false
 
   @doc """
   Remove a UTF8 BOM if exists.
   """
-  def remove_utf8_bom(_), do: raise "TODO: Implement me!"
+  def remove_utf8_bom(<< 0xEF, 0xBB, 0xBF, rest :: binary >>), do: rest
+  def remove_utf8_bom(rest), do: rest
 
   @doc """
   Add a UTF8 BOM if not exists.
   """
-  def add_utf8_bom(_), do: raise "TODO: Implement me!"
+  def add_utf8_bom(shorty), do: << 0xEF, 0xBB, 0xBF >> <> remove_utf8_bom(shorty)
 
   @doc """
   Detecting types of images by their first bytes / magic numbers.
@@ -23,7 +24,11 @@ defmodule BinaryKata do
   @see https://en.wikipedia.org/wiki/Portable_Network_Graphics
   @see https://en.wikipedia.org/wiki/GIF
   """
-  def image_type!(_), do: raise "TODO: Implement me!"
+  def image_type!(<<0xff, 0xd8, 0xff, _ :: binary >>), do: :jfif
+  def image_type!(<<0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, _ :: binary >> ), do: :png
+  def image_type!(<<"GIF87a", _ :: binary >>), do: :gif
+  def image_type!(<<"GIF89a", _ :: binary >>), do: :gif
+  def image_type!(_), do: :unknown
 
   @doc """
   Get the width and height from a GIF image.
@@ -32,7 +37,7 @@ defmodule BinaryKata do
   `width` will be little-endian in byte 7 and 8.
   `height` will be little-endian in byte 9 and 10.
   """
-  def gif_dimensions!(_), do: raise "TODO: Implement me!"
+  def gif_dimensions!(<<"GIF89a", width::16-little, height::16-little, _::binary >>), do: {width, height}
 
   @doc """
   Parsing Payload of a ARP packet. Padding will be omitted.