Fix content-type for HEAD '.jpg'

src/invidious.cr

@@ -5168,7 +5168,7 @@ get "/sb/:id/:storyboard/:index" do |env|
       env.response.headers[key] = value
     end
 
-    if response.status_code == 304
+    if response.status_code >= 400
       break
     end
 

src/invidious/helpers/handlers.cr

@@ -33,6 +33,11 @@ class Kemal::RouteHandler
       raise Kemal::Exceptions::CustomException.new(context)
     end
 
+    if context.request.method == "HEAD" &&
+       context.request.path.ends_with? ".jpg"
+      context.response.headers["Content-Type"] = "image/jpeg"
+    end
+
     context.response.print(content)
     context
   end