diff --git a/agb-image-converter/src/colour.rs b/agb-image-converter/src/colour.rs
index cba2a831..3f12001e 100644
--- a/agb-image-converter/src/colour.rs
+++ b/agb-image-converter/src/colour.rs
@@ -1,6 +1,6 @@
-use std::str::FromStr;
+use std::{fmt, str::FromStr};
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Colour {
     pub r: u8,
     pub g: u8,
@@ -8,6 +8,18 @@ pub struct Colour {
     pub a: u8,
 }
 
+impl fmt::Debug for Colour {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "#{:02x}{:02x}{:02x}", self.r, self.g, self.b)?;
+
+        if self.a != 0xff {
+            write!(f, "{:02x}", self.a)?;
+        }
+
+        Ok(())
+    }
+}
+
 impl Colour {
     pub fn from_rgb(r: u8, g: u8, b: u8, a: u8) -> Self {
         Colour { r, g, b, a }
@@ -55,7 +67,7 @@ impl quickcheck::Arbitrary for Colour {
             vec![
                 Colour::from_rgb(0, 0, 0, 0),
                 Colour::from_rgb(self.r, self.g, self.b, 0),
-                self.clone(),
+                *self,
             ]
             .into_iter(),
         )
diff --git a/agb-image-converter/src/palette16.rs b/agb-image-converter/src/palette16.rs
index a501374c..acdd4c0b 100644
--- a/agb-image-converter/src/palette16.rs
+++ b/agb-image-converter/src/palette16.rs
@@ -164,10 +164,6 @@ impl Palette16Optimiser {
         let packed_palettes =
             pagination_packing::overload_and_remove::<_, _, Vec<_>>(&palettes_to_optimise, 16);
 
-        if packed_palettes.len() > 16 {
-            return Err(DoesNotFitError(packed_palettes.len()));
-        }
-
         let optimised_palettes = packed_palettes
             .iter()
             .map(|packed_palette| {
@@ -176,6 +172,10 @@ impl Palette16Optimiser {
             })
             .collect::<Vec<_>>();
 
+        if optimised_palettes.len() > 16 {
+            return Err(DoesNotFitError(packed_palettes.len()));
+        }
+
         let mut assignments = vec![0; self.palettes.len()];
 
         for (i, overall_palette) in self.palettes.iter().enumerate() {