Search By Image: https://addons.mozilla.org/en-US/android/addon/search_by_ima...
Translate Now: https://addons.mozilla.org/en-US/android/addon/translate-now...
Translate Now: https://addons.mozilla.org/en-US/android/addon/translate-now...
Which is the reason I believe Google Translate cannot be used to implement this functionality by third parties. (like how DDG cannot use google's search results)