Using Yarn w/Rails 5.1, Getting 404 Error for jquery-ui-dist Images

I am using Yarn with Rails 5.1
I have successfully pulled in the css and js for jquery-ui-dist

ui-icons are returning a 404 error in browser. All other functionality works as expected.
application.css

*= require_self
*= require jquery-ui-dist/jquery-ui
...

application.js

//= require_self
//= require jquery/dist/jquery
//= require jquery-ui-dist/jquery-ui
//= require jquery_ujs
...

package.json

...
 "jquery-ui-dist": "^1.12.1",
 "jquery-ujs": "^1.2.2",
...

from the console:

GET http://localhost:3000/assets/images/ui-icons_444444_256x240.png 404 (Not Found)