There are a number of online stock imagery providers that you can purchase images from.
Images can be purchased from a range of stock photo providers. Before buying an image, research your market place to help you find imagery most relevant to your target market.
You need a license or permissions to use imagery on your landing page, for example, you can't download an image of a celebrity, or a random couple from Google without the right permissions. This could have huge repercussions, so to be on the safe side, ensure you purchase all images and only use them if you have permission to do so.
Make sure that your imagery will help you maintain a unique and consistent brand image, and check that the image you purchase has a high enough resolution to fit all the devices that your site may be accessed through. Popular stock photo providers include: