diff --git a/lib/cloudex/uploaded_image.ex b/lib/cloudex/uploaded_image.ex
index 8813ef8..a213856 100644
--- a/lib/cloudex/uploaded_image.ex
+++ b/lib/cloudex/uploaded_image.ex
@@ -46,13 +46,13 @@ defmodule Cloudex.UploadedImage do
         }
 
   @type eager_transformations :: list(%{
-    "bytes" => non_neg_integer,
-    "format" => String.t(),
-    "height" => non_neg_integer,
-    "secure_url" => String.t(),
-    "transformation" => String.t(),
-    "url" => String.t(),
-    "width" => non_neg_integer
+    :bytes => non_neg_integer,
+    :format => String.t(),
+    :height => non_neg_integer,
+    :secure_url => String.t(),
+    :transformation => String.t(),
+    :url => String.t(),
+    :width => non_neg_integer
   })
 
   defstruct bytes: nil,