diff --git a/api.md b/api.md
index 9043224..8a639af 100644
--- a/api.md
+++ b/api.md
@@ -480,6 +480,15 @@ defmodule AppWeb.APITest do
     }
   }
 
+  # image with invalid content type
+  @invalid_content_type_image %{
+    "" => %Plug.Upload{
+      content_type: "image/xyz",
+      filename: "phoenix.xyz",
+      path: [:code.priv_dir(:app), "static", "images", "phoenix.xyz"] |> Path.join()
+    }
+  }
+
   test "upload succeeds (happy path)", %{conn: conn} do
     conn = post(conn, ~p"/api/images", @create_attrs)
 
@@ -538,6 +547,14 @@ defmodule AppWeb.APITest do
            }
   end
 
+  test "image file with invalid content type should return appropriate error", %{conn: conn} do
+    conn = post(conn, ~p"/api/images", @invalid_content_type_image)
+
+    assert Map.get(Jason.decode!(response(conn, 400)), "errors") == %{
+             "detail" => "Error uploading file. The content type of the uploaded file is not valid."
+           }
+  end
+
   test "file with invalid binary data type and extension should return error. ", %{conn: conn} do
     conn = post(conn, ~p"/api/images", @empty_image)
 
@@ -733,6 +750,12 @@ the possible returning values from `upload/1`.
               "Error uploading file. The contents of the uploaded file may be empty or invalid."
           })
 
+        {:error, :invalid_extension} ->
+          render(conn |> put_status(400), %{
+            body:
+              "Error uploading file. The content type of the uploaded file is not valid."
+          })
+
         _ ->
           render(conn |> put_status(400), %{
             body: "There was an error uploading the file. Please try again later."
diff --git a/lib/app_web/controllers/api_controller.ex b/lib/app_web/controllers/api_controller.ex
index ec5b10e..a5858f5 100644
--- a/lib/app_web/controllers/api_controller.ex
+++ b/lib/app_web/controllers/api_controller.ex
@@ -12,6 +12,12 @@ defmodule AppWeb.ApiController do
         {:error, :failure_read} ->
           render(conn |> put_status(400), %{body: "Error uploading file. Failure reading file."})
 
+        {:error, :invalid_extension} ->
+          render(conn |> put_status(400), %{
+            body:
+              "Error uploading file. The content type of the uploaded file is not valid."
+          })
+
         {:error, :invalid_cid} ->
           render(conn |> put_status(400), %{
             body:
diff --git a/test/app_web/api_test.exs b/test/app_web/api_test.exs
index d8b272b..ebc0115 100644
--- a/test/app_web/api_test.exs
+++ b/test/app_web/api_test.exs
@@ -66,6 +66,15 @@ defmodule AppWeb.APITest do
     }
   }
 
+  # image with invalid content type
+  @invalid_content_type_image %{
+    "" => %Plug.Upload{
+      content_type: "image/xyz",
+      filename: "phoenix.xyz",
+      path: [:code.priv_dir(:app), "static", "images", "phoenix.xyz"] |> Path.join()
+    }
+  }
+
   test "upload succeeds (happy path)", %{conn: conn} do
     conn = post(conn, ~p"/api/images", @create_attrs)
 
@@ -124,6 +133,14 @@ defmodule AppWeb.APITest do
            }
   end
 
+  test "image file with invalid content type should return appropriate error", %{conn: conn} do
+    conn = post(conn, ~p"/api/images", @invalid_content_type_image)
+
+    assert Map.get(Jason.decode!(response(conn, 400)), "errors") == %{
+             "detail" => "Error uploading file. The content type of the uploaded file is not valid."
+           }
+  end
+
   test "file with invalid binary data type and extension should return error. ", %{conn: conn} do
     conn = post(conn, ~p"/api/images", @empty_image)