diff --git a/src/ImageSharp/Formats/Webp/Lossless/Vp8LBackwardRefs.cs b/src/ImageSharp/Formats/Webp/Lossless/Vp8LBackwardRefs.cs
index 502728b15f..fca4ec59f6 100644
--- a/src/ImageSharp/Formats/Webp/Lossless/Vp8LBackwardRefs.cs
+++ b/src/ImageSharp/Formats/Webp/Lossless/Vp8LBackwardRefs.cs
@@ -7,7 +7,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossless
 {
     internal class Vp8LBackwardRefs
     {
-        public Vp8LBackwardRefs() => this.Refs = new List<PixOrCopy>();
+        public Vp8LBackwardRefs(int pixels) => this.Refs = new List<PixOrCopy>(pixels);
 
         /// <summary>
         /// Gets or sets the common block-size.
diff --git a/src/ImageSharp/Formats/Webp/Lossless/Vp8LEncoder.cs b/src/ImageSharp/Formats/Webp/Lossless/Vp8LEncoder.cs
index 8ca80d5ab4..adabd0ac3f 100644
--- a/src/ImageSharp/Formats/Webp/Lossless/Vp8LEncoder.cs
+++ b/src/ImageSharp/Formats/Webp/Lossless/Vp8LEncoder.cs
@@ -130,7 +130,7 @@ namespace SixLabors.ImageSharp.Formats.Webp.Lossless
             int refsBlockSize = ((pixelCount - 1) / MaxRefsBlockPerImage) + 1;
             for (int i = 0; i < this.Refs.Length; i++)
             {
-                this.Refs[i] = new Vp8LBackwardRefs
+                this.Refs[i] = new Vp8LBackwardRefs(pixelCount)
                 {
                     BlockSize = refsBlockSize < MinBlockSize ? MinBlockSize : refsBlockSize
                 };