Scryfall is rolling out support for high resolution card images. We currently have all of Standard available, and new sets are being added daily.
For developers: Card objects in the API now have an image_uris property, which will be populated with different image sizes if the card in question has high-res imaging available. Note that many cards (especially promos) will not have these fields available immediately. You should handle both situations in your code.
We hope you really enjoy this update. We want to support content creators, app builders, and anyone else that needs high-resolution images to do their work. Please let us know what you think! 🚀