I want to upload images in my cakephp 3.0 app. But I get the error message:
Notice (8): Undefined index: Images [APP/Controller/ImagesController.php, line 55
We're using https://github.com/josegonzalez/cakephp-upload with great success in our production app, and has done so for quite some time.
Has awesome support for using "Flysystem" (https://flysystem.thephpleague.com/) as well - which is abstractions from specific file system(s) - so moving from normal local file system to S3 is a no-brainer, or Dropbox or whatever place you want :-)
You can find related (high quality) plugins on file uploading right here: https://github.com/FriendsOfCake/awesome-cakephp#files - I've used "Proffer" with success as well, and it's by no means "almost done" or anything alike - both has all my recommendations and is in my eyes production ready!