diff --git a/components/script/dom/imagedata.rs b/components/script/dom/imagedata.rs
index 39e3b061711..cc7699bd5f3 100644
--- a/components/script/dom/imagedata.rs
+++ b/components/script/dom/imagedata.rs
@@ -15,6 +15,7 @@ use js::jsapi::{Heap, JSObject};
 use js::rust::Runtime;
 use js::typedarray::{CreateWith, Uint8ClampedArray};
 use std::borrow::Cow;
+use std::convert::TryInto;
 use std::default::Default;
 use std::ptr;
 use std::ptr::NonNull;
@@ -113,7 +114,12 @@ impl ImageData {
         let len = width * height * 4;
         let cx = global.get_cx();
         rooted!(in (*cx) let mut array = ptr::null_mut::<JSObject>());
-        Uint8ClampedArray::create(*cx, CreateWith::Length(len), array.handle_mut()).unwrap();
+        Uint8ClampedArray::create(
+            *cx,
+            CreateWith::Length(len.try_into().unwrap()),
+            array.handle_mut(),
+        )
+        .unwrap();
         (*imagedata).data.set(array.get());
 
         Ok(reflect_dom_object(imagedata, global))