Add rich text editor / TinyMCE to image alt text field

Hello, I want to utilize the image alt text field and display the content on my site. I would like to know if anyone knows how to add a rich text editor/TinyMCE to this field? I need image captions display with rich text formatting, and the only image info field that allows for this by default (the description field) is basically useless and far too difficult to get to display. Alt text can be displayed pretty easily but only in simple text format. (I need to be able to modify text as bold, italic etc. directly in this field. in the media library or image info editor.)

Any ideas? Thanks!