Sinclair Ferguson made the following comment:
Fifty years ago, to be an evangelical implied a deep commitment to the great creedal verities of historic Christianity. But it also included certain distinctive views about the nature of the work of Christ and how the blessings of salvation are received.You may be interested to read this thoughtful essay by Michael Horton:
At the heart of these lay the authority of Scripture and the twin convictions that the death of Christ involved penal substitution, and that the beginning of the Christian life was marked by justification by faith alone.
To be or not to be: The Uneasy Relationship between Reformed Christianity and American Evangelicalism
The painting, by the way, is by Manet. It is part of the collection of Impressionist works held at Cardiff Museum.