diff --git a/ImageFunctions/Thumbnail.cs b/ImageFunctions/Thumbnail.cs
index c69ba71..daacac8 100644
--- a/ImageFunctions/Thumbnail.cs
+++ b/ImageFunctions/Thumbnail.cs
@@ -95,7 +95,7 @@ public static async Task Run(
                         using (var output = new MemoryStream())
                         using (Image<Rgba32> image = Image.Load(input))
                         {
-                            var divisor = image.Width / thumbnailWidth;
+                            var divisor = (double)image.Width / thumbnailWidth;
                             var height = Convert.ToInt32(Math.Round((decimal)(image.Height / divisor)));
 
                             image.Mutate(x => x.Resize(thumbnailWidth, height));