We study the perception of ambiance of places captured in social media images by both machines and crowdworkers. This task is challenging due to the subjective nature of the ambiance construct as well as the large variety in layout, style, and visual characteristics of venues. For machine recognition of ambiance, we use state-of-the-art Residual Deep Convolutional Neural Networks (ResNets), followed by gradient-weighted class activation mapping (Grad-CAM) visualizations. This form of visual explanation obtained from the trained ResNet-50 models were assessed by crowdworkers based on a carefully designed crowdsourcing task, in which both visual ambiance cues of venues and subjective assessment of Grad-CAM results were collected and analyzed. The results show that paintings, photos, and decorative items are strong cues for artsy ambiance, whereas type of utensils, type of lamps and presence of flowers may indicate formal ambiance. Layout and design-related cues such as type of chairs, type of tables/tablecloth and type of windows are noted to have impact for both ambiances. Overall, the ambiance visual cue recognition results are promising, and the crowd-based assessment approach may motivate other studies on subjective perception of place attributes.