diff --git a/src/add-sample.ts b/src/add-sample.ts
index 3bc2044..23ef41e 100644
--- a/src/add-sample.ts
+++ b/src/add-sample.ts
@@ -53,7 +53,7 @@ export function addSample(
       context2d.drawImage(img, 0, 0, canvas.width, canvas.height)
       return addSample(
         context,
-        context2d.getImageData(0, 0, img.width, img.height).data,
+        context2d.getImageData(0, 0, canvas.width, canvas.height).data,
         options,
       )
     })
diff --git a/src/create-palette.ts b/src/create-palette.ts
index c55a851..60481a4 100644
--- a/src/create-palette.ts
+++ b/src/create-palette.ts
@@ -58,7 +58,9 @@ export function createPalette(options?: Options | Context): Palette {
 
       return result
     },
-    generate(options) {
+    generate(options = {}) {
+      const { clearSamples = true } = options
+      if (clearSamples) previousSample = null
       generate(context, options)
       return this
     },