[FEATURE REQUEST] Easily customize 404 responses/errors

[stefanofusai]

It would be nice to customize responses on pages that don't match any of the "valid" routes.
Right now, visiting the root returns this response:

While visiting a non existing path redirects to this repo. It would be nice to customize this kind of edge cases, as well as maybe the error messages such as Something went wrong! or Source image is unreachable

[wottpal]

Thumbs up on this, additionally I'm thinking of adding the option for a fallback image (which is always served when the requested one is not available). Would you be open for a PR, @andrasbacsai?

[lucasdu4rte]

Thumbs up on this, additionally I'm thinking of adding the option for a fallback image (which is always served when the requested one is not available). Would you be open for a PR, @andrasbacsai?

@wottpal would be perfect, because in some random moments NextImageTransformation is not being able to download the images (running inside coolify/docker), and I need to show a “standard” image until it is solved