diff --git a/res/character_spritesheet.dat b/res/.mci
similarity index 100%
rename from res/character_spritesheet.dat
rename to res/.mci
diff --git a/res/character_spritesheet.mci b/res/character_spritesheet.mci
new file mode 100644
index 0000000..6f93cd5
Binary files /dev/null and b/res/character_spritesheet.mci differ
diff --git a/res/tiles/dirt.dat b/res/tiles/dirt.mci
similarity index 100%
rename from res/tiles/dirt.dat
rename to res/tiles/dirt.mci
diff --git a/res/tiles/gravel.dat b/res/tiles/gravel.mci
similarity index 100%
rename from res/tiles/gravel.dat
rename to res/tiles/gravel.mci
diff --git a/res/tiles/ice.dat b/res/tiles/ice.mci
similarity index 100%
rename from res/tiles/ice.dat
rename to res/tiles/ice.mci
diff --git a/res/tiles/lava.dat b/res/tiles/lava.mci
similarity index 100%
rename from res/tiles/lava.dat
rename to res/tiles/lava.mci
diff --git a/res/tiles/null.dat b/res/tiles/null.mci
similarity index 100%
rename from res/tiles/null.dat
rename to res/tiles/null.mci
diff --git a/res/tiles/water.dat b/res/tiles/water.mci
similarity index 100%
rename from res/tiles/water.dat
rename to res/tiles/water.mci
diff --git a/res/tileset.txt b/res/tileset.txt
index 23e1cbb..dbdbebd 100644
--- a/res/tileset.txt
+++ b/res/tileset.txt
@@ -8,7 +8,7 @@
 # <char> <imagepath> [keywords]
 #
 # The image path is relative to res/ folder.
-# Do not include the file extension (always PNG).
+# Do not include the file extension (always MCI).
 # If image path is null, it won't render.
 #
 # The OPTIONAL case-insensitive keywords are:
diff --git a/src/game/Game.java b/src/game/Game.java
index e662bc9..563f0a2 100644
--- a/src/game/Game.java
+++ b/src/game/Game.java
@@ -817,7 +817,7 @@ public int charId(boolean down, boolean right, boolean up, boolean left) {
 
     // loads a bufferedimage in by filename
     public BufferedImage getImage(String name) throws Exception {
-        byte[] imagedata = decompress(Files.readAllBytes(new File("../res/" + name + ".dat").toPath()));
+        byte[] imagedata = decompress(Files.readAllBytes(new File("../res/" + name + ".mci").toPath()));
         int xmax = imagedata[0];
         int ymax = (imagedata.length - 1) / xmax;
         BufferedImage b = new BufferedImage(xmax, ymax, BufferedImage.TYPE_INT_ARGB);
@@ -830,6 +830,7 @@ public BufferedImage getImage(String name) throws Exception {
         return b;
     }
 
+    // decompresses the data into a byte array
     public static byte[] decompress(byte[] data) throws IOException, DataFormatException {
         Inflater inflater = new Inflater();
         inflater.setInput(data);
@@ -881,6 +882,7 @@ class Tile {
 }
 
 class Colors {
+    // all of the colors in the images
     public static final int[] colors = new int[] {
         0xff747474,
         0xff24188c,
diff --git a/src/tileeditor/Main.java b/src/tileeditor/Main.java
index 41d5a2c..40f269b 100644
--- a/src/tileeditor/Main.java
+++ b/src/tileeditor/Main.java
@@ -94,7 +94,7 @@ public class Main {
     public static void main(String[] args) {
         fc.setAcceptAllFileFilterUsed(true);
         fc.setMultiSelectionEnabled(false);
-        fc.setFileFilter(new FileNameExtensionFilter(".dat File", "dat"));
+        fc.setFileFilter(new FileNameExtensionFilter("Mooncat Compressed Image (.mci)", "mci"));
         refresh();
         frame = new JFrame("Tile Editor");
         panel1 = new JPanel() {
@@ -260,8 +260,8 @@ public static void save() {
                 colormap[0] = (byte)xmax;
                 File f = fc.getSelectedFile();
                 String filePath = f.getAbsolutePath();
-                if(!filePath.endsWith(".dat")) {
-                    f = new File(filePath + ".dat");
+                if(!filePath.endsWith(".mci")) {
+                    f = new File(filePath + ".mci");
                 }
                 Files.write(f.toPath(), compress(colormap));
             } catch(Exception e) {