diff --git a/lib/mobilizon/media/file.ex b/lib/mobilizon/media/file.ex
index a424b8c63..2574a012b 100644
--- a/lib/mobilizon/media/file.ex
+++ b/lib/mobilizon/media/file.ex
@@ -9,6 +9,7 @@ defmodule Mobilizon.Media.File do
     field(:name, :string)
     field(:url, :string)
     field(:content_type, :string)
+    field(:size, :integer)
 
     timestamps()
   end
@@ -16,7 +17,7 @@ defmodule Mobilizon.Media.File do
   @doc false
   def changeset(picture, attrs) do
     picture
-    |> cast(attrs, [:name, :url, :content_type])
+    |> cast(attrs, [:name, :url, :content_type, :size])
     |> validate_required([:name, :url])
   end
 end
diff --git a/lib/mobilizon_web/resolvers/picture.ex b/lib/mobilizon_web/resolvers/picture.ex
index 18c0caa59..c98a0346a 100644
--- a/lib/mobilizon_web/resolvers/picture.ex
+++ b/lib/mobilizon_web/resolvers/picture.ex
@@ -36,7 +36,8 @@ defmodule MobilizonWeb.Resolvers.Picture do
   @spec do_fetch_picture(String.t()) :: {:ok, Picture.t()} | {:error, :not_found}
   defp do_fetch_picture(picture_id) do
     with %Picture{id: id, file: file} = _pic <- Media.get_picture(picture_id) do
-      {:ok, %{name: file.name, url: file.url, id: id}}
+      {:ok,
+       %{name: file.name, url: file.url, id: id, content_type: file.content_type, size: file.size}}
     else
       _err ->
         {:error, "Picture with ID #{picture_id} was not found"}
@@ -50,11 +51,23 @@ defmodule MobilizonWeb.Resolvers.Picture do
         }
       }) do
     with {:is_owned, true, _actor} <- User.owns_actor(user, actor_id),
-         {:ok, %{"url" => [%{"href" => url}]}} <- MobilizonWeb.Upload.store(file),
-         args <- Map.put(args, :url, url),
+         {:ok, %{"url" => [%{"href" => url, "mediaType" => content_type}], "size" => size}} <-
+           MobilizonWeb.Upload.store(file),
+         args <-
+           args
+           |> Map.put(:url, url)
+           |> Map.put(:size, size)
+           |> Map.put(:content_type, content_type),
          {:ok, picture = %Picture{}} <-
            Media.create_picture(%{"file" => args, "actor_id" => actor_id}) do
-      {:ok, %{name: picture.file.name, url: picture.file.url, id: picture.id}}
+      {:ok,
+       %{
+         name: picture.file.name,
+         url: picture.file.url,
+         id: picture.id,
+         content_type: picture.file.content_type,
+         size: picture.file.size
+       }}
     else
       {:is_owned, false} ->
         {:error, "Actor id is not owned by authenticated user"}
diff --git a/lib/mobilizon_web/schema/picture.ex b/lib/mobilizon_web/schema/picture.ex
index d14b3ebf3..e241ace92 100644
--- a/lib/mobilizon_web/schema/picture.ex
+++ b/lib/mobilizon_web/schema/picture.ex
@@ -11,6 +11,8 @@ defmodule MobilizonWeb.Schema.PictureType do
     field(:alt, :string, description: "The picture's alternative text")
     field(:name, :string, description: "The picture's name")
     field(:url, :string, description: "The picture's full URL")
+    field(:content_type, :string, description: "The picture's detected content type")
+    field(:size, :integer, description: "The picture's size")
   end
 
   @desc "An attached picture or a link to a picture"
diff --git a/lib/mobilizon_web/upload.ex b/lib/mobilizon_web/upload.ex
index fac4fffbc..24ad765eb 100644
--- a/lib/mobilizon_web/upload.ex
+++ b/lib/mobilizon_web/upload.ex
@@ -52,9 +52,10 @@ defmodule MobilizonWeb.Upload do
           name: String.t(),
           tempfile: String.t(),
           content_type: String.t(),
-          path: String.t()
+          path: String.t(),
+          size: integer()
         }
-  defstruct [:id, :name, :tempfile, :content_type, :path]
+  defstruct [:id, :name, :tempfile, :content_type, :path, :size]
 
   @spec store(source, options :: [option()]) :: {:ok, Map.t()} | {:error, any()}
   def store(upload, opts \\ []) do
@@ -66,7 +67,7 @@ defmodule MobilizonWeb.Upload do
          {:ok, url_spec} <- MobilizonWeb.Uploaders.Uploader.put_file(opts.uploader, upload) do
       {:ok,
        %{
-         "type" => opts.activity_type,
+         "type" => opts.activity_type || get_type(upload.content_type),
          "url" => [
            %{
              "type" => "Link",
@@ -74,6 +75,7 @@ defmodule MobilizonWeb.Upload do
              "href" => url_from_spec(upload, opts.base_url, url_spec)
            }
          ],
+         "size" => upload.size,
          "name" => Map.get(opts, :description) || upload.name
        }}
     else
@@ -100,7 +102,7 @@ defmodule MobilizonWeb.Upload do
           {Mobilizon.CommonConfig.get!([:instance, :avatar_upload_limit]), "Image"}
 
         _ ->
-          {Mobilizon.CommonConfig.get!([:instance, :upload_limit]), "Document"}
+          {Mobilizon.CommonConfig.get!([:instance, :upload_limit]), nil}
       end
 
     %{
@@ -119,14 +121,15 @@ defmodule MobilizonWeb.Upload do
   end
 
   defp prepare_upload(%Plug.Upload{} = file, opts) do
-    with :ok <- check_file_size(file.path, opts.size_limit),
+    with {:ok, size} <- check_file_size(file.path, opts.size_limit),
          {:ok, content_type, name} <- Mobilizon.MIME.file_mime_type(file.path, file.filename) do
       {:ok,
        %__MODULE__{
          id: UUID.generate(),
          name: name,
          tempfile: file.path,
-         content_type: content_type
+         content_type: content_type,
+         size: size
        }}
     end
   end
@@ -134,7 +137,7 @@ defmodule MobilizonWeb.Upload do
   defp check_file_size(path, size_limit) when is_integer(size_limit) and size_limit > 0 do
     with {:ok, %{size: size}} <- File.stat(path),
          true <- size <= size_limit do
-      :ok
+      {:ok, size}
     else
       false -> {:error, :file_too_large}
       error -> error
@@ -143,6 +146,16 @@ defmodule MobilizonWeb.Upload do
 
   defp check_file_size(_, _), do: :ok
 
+  @picture_content_types ["image/png", "image/jpg", "image/jpeg", "image/webp"]
+  # Return whether the upload is a picture or not
+  defp get_type(content_type) do
+    if content_type in @picture_content_types do
+      "Image"
+    else
+      "Document"
+    end
+  end
+
   defp url_from_spec(%__MODULE__{name: name}, base_url, {:file, path}) do
     path =
       URI.encode(path, &char_unescaped?/1) <>
diff --git a/lib/service/activity_pub/utils.ex b/lib/service/activity_pub/utils.ex
index 1e81d1291..fdd469eee 100644
--- a/lib/service/activity_pub/utils.ex
+++ b/lib/service/activity_pub/utils.ex
@@ -209,12 +209,15 @@ defmodule Mobilizon.Service.ActivityPub.Utils do
   Save picture data from raw data and return AS Link data.
   """
   def make_picture_data(%{picture: picture}) do
-    with {:ok, %{"url" => [%{"href" => url}]}} <- MobilizonWeb.Upload.store(picture.file),
+    with {:ok, %{"url" => [%{"href" => url, "mediaType" => content_type}], "size" => size}} <-
+           MobilizonWeb.Upload.store(picture.file),
          {:ok, %Picture{file: _file} = pic} <-
            Mobilizon.Media.create_picture(%{
              "file" => %{
                "url" => url,
-               "name" => picture.name
+               "name" => picture.name,
+               "content_type" => content_type,
+               "size" => size
              },
              "actor_id" => picture.actor_id
            }) do
diff --git a/test/mobilizon_web/resolvers/picture_resolver_test.exs b/test/mobilizon_web/resolvers/picture_resolver_test.exs
index 63e71dea0..e1dde528d 100644
--- a/test/mobilizon_web/resolvers/picture_resolver_test.exs
+++ b/test/mobilizon_web/resolvers/picture_resolver_test.exs
@@ -21,7 +21,9 @@ defmodule MobilizonWeb.Resolvers.PictureResolverTest do
         picture(id: "#{id}") {
             name,
             alt,
-            url
+            url,
+            content_type,
+            size
         }
       }
       """
@@ -32,6 +34,11 @@ defmodule MobilizonWeb.Resolvers.PictureResolverTest do
 
       assert json_response(res, 200)["data"]["picture"]["name"] == picture.file.name
 
+      assert json_response(res, 200)["data"]["picture"]["content_type"] ==
+               picture.file.content_type
+
+      assert json_response(res, 200)["data"]["picture"]["size"] == 13_120
+
       assert json_response(res, 200)["data"]["picture"]["url"] =~
                MobilizonWeb.Endpoint.url()
     end
@@ -68,7 +75,9 @@ defmodule MobilizonWeb.Resolvers.PictureResolverTest do
               actor_id: #{actor.id}
             ) {
                 url,
-                name
+                name,
+                content_type,
+                size
               }
         }
       """
@@ -91,6 +100,8 @@ defmodule MobilizonWeb.Resolvers.PictureResolverTest do
         )
 
       assert json_response(res, 200)["data"]["uploadPicture"]["name"] == picture.name
+      assert json_response(res, 200)["data"]["uploadPicture"]["content_type"] == "image/png"
+      assert json_response(res, 200)["data"]["uploadPicture"]["size"] == 10_097
       assert json_response(res, 200)["data"]["uploadPicture"]["url"]
     end
 
diff --git a/test/mobilizon_web/upload_test.exs b/test/mobilizon_web/upload_test.exs
index d9ebe606d..39f1bb656 100644
--- a/test/mobilizon_web/upload_test.exs
+++ b/test/mobilizon_web/upload_test.exs
@@ -21,7 +21,11 @@ defmodule Mobilizon.UploadTest do
 
       {:ok, data} = Upload.store(file)
 
-      assert %{"url" => [%{"href" => url}]} = data
+      assert %{
+               "url" => [%{"href" => url, "mediaType" => "image/jpeg"}],
+               "size" => 13_227,
+               "type" => "Image"
+             } = data
 
       assert String.starts_with?(url, MobilizonWeb.Endpoint.url() <> "/media/")
     end
diff --git a/test/support/factory.ex b/test/support/factory.ex
index 65804f631..5362bbe9c 100644
--- a/test/support/factory.ex
+++ b/test/support/factory.ex
@@ -174,7 +174,8 @@ defmodule Mobilizon.Factory do
     %Mobilizon.Media.File{
       name: "My Picture",
       url: MobilizonWeb.Endpoint.url() <> "/uploads/something",
-      content_type: "image/png"
+      content_type: "image/png",
+      size: 13_120
     }
   end