You're using Culturegrid and would like to display a large image of one of the results. Oh - it only supplies a thumbnail?
No fear - run the URL of the resulting web page through this scraper and it will try its best to give you the image on the page most likely to be the image you want.
It's not perfect, but it should improve over time.
Try it here: http://culturescraper.heroku.com
Contact me at Stef.io