Wish: option not to change extension

[markstos]

Is your feature request related to a problem? Please describe.

I'm trying to optimize 2,000 images across many directories.

A challenge I'm running into that my ".jpegs" have been renamed to ".jpg".

Because all the new images need to have the exact same path at the end of the project, it would be more convenient if a file that started out was a ".jpeg" stayed a dot ".jpg".

Describe the solution you'd like

First possibility is to change the behavior so that when the output format matches the input format, always preserve the extension.

Second possibility is to preserve backwards compatibility with the current behavior, add a flag --preserve-extension so when the input and output format matches, keep the extension only if the user explicitly asks for that.

Does other service/app have this feature?

I presume.