Art on a Postcard, the charity founded to raise funds for the Hepatitis C Trust, is dedicating its next auction of 4in-by-6in artworks to War Child, which provides aid to children caught in conflict zones. They are currently working to get steriliser, clean water, soap and other essentials to children in Gaza. Bidding starts at £50 for works including Dave Gamble’s polaroids of Andy Warhol’s possessions, abstract works by Mandy El-Sayegh and portraitist Sarah Ball’s close-up study of a face, its eyes looking steadily ahead. All proceeds go towards War Child. Baya Simons Bidding opens on 23 April. Original works can be viewed at The Fitzrovia Gallery on 30 April from 10am to 6pm. The auction closes on 7 May; artonapostcard.com