You can now use the automatic alt text extension to generate alt text on the fly directly from the authoring experience.
The automatic alt text extension now has 2 modes: automatic and generated.
In automatic mode (the default), the extension retrieves image alt text generated by the Automatic Alt Text service.
In the new generated mode you can generate alt text on the fly from within the authoring experience. Alt text can be generated for multiple locales using the alt text template in Content Studio.
Read more on the Automatic alt text extension page.