diff --git a/src/encoder.rs b/src/encoder.rs
index 37e7c63..369ee23 100644
--- a/src/encoder.rs
+++ b/src/encoder.rs
@@ -332,26 +332,28 @@ impl PictureWrapper {
         }
 
         if unsafe {
+            let size = color_mode.size() as i32;
+
             match color_mode {
                 ColorMode::Rgba => webp::WebPPictureImportRGBA(
                     &mut self.picture,
                     data.as_ptr(),
-                    self.picture.width * 4,
+                    self.picture.width * size,
                 ),
                 ColorMode::Bgra => webp::WebPPictureImportBGRA(
                     &mut self.picture,
                     data.as_ptr(),
-                    self.picture.width * 4,
+                    self.picture.width * size,
                 ),
                 ColorMode::Rgb => webp::WebPPictureImportRGB(
                     &mut self.picture,
                     data.as_ptr(),
-                    self.picture.width * 3,
+                    self.picture.width * size,
                 ),
                 ColorMode::Bgr => webp::WebPPictureImportBGR(
                     &mut self.picture,
                     data.as_ptr(),
-                    self.picture.width * 3,
+                    self.picture.width * size,
                 ),
             }
         } == 0
diff --git a/src/lib.rs b/src/lib.rs
index 24fd79c..5dc9356 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -49,12 +49,11 @@ pub enum ColorMode {
 }
 
 impl ColorMode {
+    /// Return the pixel bytesize for the color mode
     pub fn size(&self) -> usize {
         match self {
-            Self::Rgb => 3,
-            Self::Rgba => 4,
-            Self::Bgra => 4,
-            Self::Bgr => 3,
+            Self::Rgb | Self::Bgr => 3,
+            Self::Rgba | Self::Bgra => 4,
         }
     }
 }