diff --git a/app/models/message/attachment.rb b/app/models/message/attachment.rb
index bc727ba..4b895ea 100644
--- a/app/models/message/attachment.rb
+++ b/app/models/message/attachment.rb
@@ -30,6 +30,7 @@ module Message::Attachment
       attachment&.analyze
     end
 
+    # A file that ffmpeg or libvips can't decode is still the message: post it without a preview.
     def process_attachment_thumbnail
       case
       when attachment.video?
@@ -37,5 +38,7 @@ module Message::Attachment
       when attachment.representable?
         attachment.representation(:thumb).processed
       end
+    rescue ActiveStorage::PreviewError, Vips::Error => error
+      Rails.logger.warn "Posted #{attachment.filename} without a preview: #{error.class}: #{error.message.lines.first&.chomp}"
     end
 end
diff --git a/test/controllers/messages_controller_test.rb b/test/controllers/messages_controller_test.rb
index 8088694..e5bfc14 100644
--- a/test/controllers/messages_controller_test.rb
+++ b/test/controllers/messages_controller_test.rb
@@ -57,6 +57,18 @@ class MessagesControllerTest < ActionDispatch::IntegrationTest
     end
   end
 
+  test "creating a message with an image that can't be decoded broadcasts the message to the room" do
+    webp = Vips::Image.new_from_file(file_fixture("moon.jpg").to_s).webpsave_buffer
+    broken = Rack::Test::UploadedFile.new(StringIO.new(webp.byteslice(0, webp.bytesize / 2)), "image/webp", original_filename: "broken.webp")
+
+    post room_messages_url(@room, format: :turbo_stream), params: { message: { attachment: broken, client_message_id: 999 } }
+
+    assert_response :success
+    assert_rendered_turbo_stream_broadcast @room, :messages, action: "append", target: [ @room, :messages ] do
+      assert_select ".message__body a[href*='broken.webp']"
+    end
+  end
+
   test "creating a message broadcasts unread room to each member" do
     @room.users.each do |member|
       assert_broadcasts UnreadRoomsChannel.stream_name_for(member.id), 1 do
diff --git a/test/models/message/attachment_test.rb b/test/models/message/attachment_test.rb
index 47d71c1..6925eb0 100644
--- a/test/models/message/attachment_test.rb
+++ b/test/models/message/attachment_test.rb
@@ -19,6 +19,20 @@ class Message::AttachmentTest < ActiveSupport::TestCase
     assert_equal message.plain_text_body, "moon.jpg"
   end
 
+  test "creating a message keeps an image that can't be decoded" do
+    webp = Vips::Image.new_from_file(file_fixture("moon.jpg").to_s).webpsave_buffer
+    message = create_unreadable_attachment_message(webp.byteslice(0, webp.bytesize / 2), "broken.webp")
+
+    assert_equal "broken.webp", message.reload.attachment.filename.to_s
+    assert_nil message.attachment.representation(:thumb).image
+  end
+
+  test "creating a message keeps a video that can't be decoded" do
+    message = create_unreadable_attachment_message(file_fixture("alpha-centuri.mov").binread(64), "broken.mov")
+
+    assert_equal "broken.mov", message.reload.attachment.filename.to_s
+    assert_not message.attachment.preview(format: :webp).image.attached?
+  end
 
   private
     def create_attachment_message(file, content_type)
@@ -27,4 +41,11 @@ class Message::AttachmentTest < ActiveSupport::TestCase
         client_message_id: "message",
         attachment: fixture_file_upload(file, content_type)
     end
+
+    def create_unreadable_attachment_message(content, filename)
+      rooms(:hq).messages.create_with_attachment! \
+        creator: users(:david),
+        client_message_id: "message",
+        attachment: { io: StringIO.new(content), filename: filename }
+    end
 end