diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85401809a..c4077c85d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 <details>
   <summary>API Changes</summary>
 
+- **Breaking:** Image description length is limited now.
 - **Breaking:** Emoji API: changed methods and renamed routes.
 - Streaming: Repeats of a user's posts will no longer be pushed to the user's stream.
 - Mastodon API: Added `pleroma.metadata.fields_limits` to /api/v1/instance
diff --git a/config/config.exs b/config/config.exs
index 9b550920c..d28a359b2 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -188,6 +188,7 @@
   background_image: "/images/city.jpg",
   instance_thumbnail: "/instance/thumbnail.jpeg",
   limit: 5_000,
+  description_limit: 5_000,
   chat_limit: 5_000,
   remote_limit: 100_000,
   upload_limit: 16_000_000,
diff --git a/docs/API/differences_in_mastoapi_responses.md b/docs/API/differences_in_mastoapi_responses.md
index 72b5984ae..d2455d5d7 100644
--- a/docs/API/differences_in_mastoapi_responses.md
+++ b/docs/API/differences_in_mastoapi_responses.md
@@ -220,6 +220,8 @@ Has theses additional parameters (which are the same as in Pleroma-API):
 `GET /api/v1/instance` has additional fields
 
 - `max_toot_chars`: The maximum characters per post
+- `chat_limit`: The maximum characters per chat message
+- `description_limit`: The maximum characters per image description
 - `poll_limits`: The limits of polls
 - `upload_limit`: The maximum upload file size
 - `avatar_upload_limit`: The same for avatars
diff --git a/docs/configuration/cheatsheet.md b/docs/configuration/cheatsheet.md
index 6759d5e93..6b640cebc 100644
--- a/docs/configuration/cheatsheet.md
+++ b/docs/configuration/cheatsheet.md
@@ -18,6 +18,7 @@ To add configuration to your config file, you can copy it from the base config.
 * `notify_email`: Email used for notifications.
 * `description`: The instance’s description, can be seen in nodeinfo and ``/api/v1/instance``.
 * `limit`: Posts character limit (CW/Subject included in the counter).
+* `discription_limit`: The character limit for image descriptions.
 * `chat_limit`: Character limit of the instance chat messages.
 * `remote_limit`: Hard character limit beyond which remote posts will be dropped.
 * `upload_limit`: File size limit of uploads (except for avatar, background, banner).
diff --git a/lib/pleroma/upload.ex b/lib/pleroma/upload.ex
index 797555bff..0fa6b89dc 100644
--- a/lib/pleroma/upload.ex
+++ b/lib/pleroma/upload.ex
@@ -63,6 +63,10 @@ def store(upload, opts \\ []) do
     with {:ok, upload} <- prepare_upload(upload, opts),
          upload = %__MODULE__{upload | path: upload.path || "#{upload.id}/#{upload.name}"},
          {:ok, upload} <- Pleroma.Upload.Filter.filter(opts.filters, upload),
+         description = Map.get(opts, :description) || upload.name,
+         {_, true} <-
+           {:description_limit,
+            String.length(description) <= Pleroma.Config.get([:instance, :description_limit])},
          {:ok, url_spec} <- Pleroma.Uploaders.Uploader.put_file(opts.uploader, upload) do
       {:ok,
        %{
@@ -75,9 +79,12 @@ def store(upload, opts \\ []) do
              "href" => url_from_spec(upload, opts.base_url, url_spec)
            }
          ],
-         "name" => Map.get(opts, :description) || upload.name
+         "name" => description
        }}
     else
+      {:description_limit, _} ->
+        {:error, :description_too_long}
+
       {:error, error} ->
         Logger.error(
           "#{__MODULE__} store (using #{inspect(opts.uploader)}) failed: #{inspect(error)}"
diff --git a/lib/pleroma/web/mastodon_api/views/instance_view.ex b/lib/pleroma/web/mastodon_api/views/instance_view.ex
index 89e48fba5..5deb0d7ed 100644
--- a/lib/pleroma/web/mastodon_api/views/instance_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/instance_view.ex
@@ -34,6 +34,8 @@ def render("show.json", _) do
       background_upload_limit: Keyword.get(instance, :background_upload_limit),
       banner_upload_limit: Keyword.get(instance, :banner_upload_limit),
       background_image: Keyword.get(instance, :background_image),
+      chat_limit: Keyword.get(instance, :chat_limit),
+      description_limit: Keyword.get(instance, :description_limit),
       pleroma: %{
         metadata: %{
           account_activation_required: Keyword.get(instance, :account_activation_required),
diff --git a/test/upload_test.exs b/test/upload_test.exs
index 2abf0edec..b06b54487 100644
--- a/test/upload_test.exs
+++ b/test/upload_test.exs
@@ -107,6 +107,19 @@ test "it returns error" do
   describe "Storing a file with the Local uploader" do
     setup [:ensure_local_uploader]
 
+    test "does not allow descriptions longer than the post limit" do
+      clear_config([:instance, :description_limit], 2)
+      File.cp!("test/fixtures/image.jpg", "test/fixtures/image_tmp.jpg")
+
+      file = %Plug.Upload{
+        content_type: "image/jpg",
+        path: Path.absname("test/fixtures/image_tmp.jpg"),
+        filename: "image.jpg"
+      }
+
+      {:error, :description_too_long} = Upload.store(file, description: "123")
+    end
+
     test "returns a media url" do
       File.cp!("test/fixtures/image.jpg", "test/fixtures/image_tmp.jpg")
 
diff --git a/test/web/mastodon_api/controllers/instance_controller_test.exs b/test/web/mastodon_api/controllers/instance_controller_test.exs
index 95ee26416..cc880d82c 100644
--- a/test/web/mastodon_api/controllers/instance_controller_test.exs
+++ b/test/web/mastodon_api/controllers/instance_controller_test.exs
@@ -32,7 +32,9 @@ test "get instance information", %{conn: conn} do
              "avatar_upload_limit" => _,
              "background_upload_limit" => _,
              "banner_upload_limit" => _,
-             "background_image" => _
+             "background_image" => _,
+             "chat_limit" => _,
+             "description_limit" => _
            } = result
 
     assert result["pleroma"]["metadata"]["account_activation_required"] != nil