Describe your issue or idea

I want to make ALT tags on images required. There is a module I could port but I think this should probably be in core and active as a default for new image fields. Side note: I also see that D8 has this in core:

screen shot 2018-06-22 at 9 36 02 am

From that D8 issue:

Alternative attribute text is required for images to ensure a site meets WCAG accessibility guidelines. When adding an image field to a content type, the alt text field is currently optional meaning Drupal sites often fail accessibility audits until alt text is added to images.

Note: This issue does not relate to images added via CKeditor. It relates to changing the default setting on the image field to require the alt attribute.

GitHub Issue #: 
3006