Please find below an alphabetical list auction houses which provided us with many of coins and banknotes images.
Don't hesitate to visit their web pages. They have a really great selection of coins and banknotes in offer.
Münzen & Medaillen GmbH (DE)
Numismatica Ars Classica NAC AG
Numismatik Lanz München
Stack's / Ponterio & Associates
Stephen Album Rare Coins
Teutoburger Münzauktion GmbH