In the ``dev`` environment, the URL ``/assets/images/duck-3c16d9220694c0e56d8648f25e6035e9.png``

is handled and returned by your Symfony app - but only if ``public/assets/`` is empty (see below).

is handled and returned by your Symfony app.

For the ``prod`` environment, before deploy, you should run:

..caution::

If you compiled your assets on your development machine, you need to delete them again,

in order to make Symfony serve the current versions from ``assets/`` again.

If you run the ``asset-map:compile`` command on your development machine,

you won't see any changes made to your assets when reloading the page.

To resolve this, delete the contents of the ``public/assets/`` directory.

This will allow your Symfony application to serve those assets dynamically again.

..tip::