In all honesty, donkeys were quite useful to humans and they still serve a very practical purpose despite all the advances of technologies. If you are hell-bent on finding Donkey posters that take these stubborn and resilient creatures seriously, you will surely find the perfect match at FulcrumGallery.com. The vast majority of the artwork though is mostly amusing and is a great addition to any collection that intents to be funny and relaxing.
Horses were preferred by artists for obvious reasons, but it is still possible to find impressionist and even classical Donkey posters. Granted they are rarely at the cornerstone of such paintings, the donkeys are still there and if the artists paid enough attention to detail, the scene itself can be enthralling.