Visit Britain provides nearly 15,000 selected copyright-free images, with a search box. The selection is obviously highly curated and high-quality, and no registration is required to download. If you have a pop-up blocker, you’ll need to whitelist to get at the hi-res magazine-quality image download link. There are a few noticeable gaps in coverage, such as the major ceramics tourism hub which is the city of Stoke-on-Trent (one picture, on a search for “Stoke-on-Trent”).