Create an impressionistic landscape painting that captures the serene beauty of a jungle scene during the golden hour of autumn. Utilize oil painting techniques on a 24x36 inch canvas to allow for rich texture and depth. In the foreground, depict dense trees adorned with vibrant autumn leaves in shades of orange, red, and yellow, creating a rich tapestry of color. A gentle river should wind gracefully through the jungle, its surface reflecting the warm hues of the low-setting sun, creating a shimmering effect. The mountains in the background should rise majestically, their rugged peaks softened by the golden light, enhancing the sense of depth. Wispy clouds drift lazily across the sky, painted in soft pastels that enhance the peaceful atmosphere. To evoke tranquility, consider adding subtle details such as birds in flight or gentle ripples in the water. The overall composition should be balanced, with the river leading the viewer's eye through the scene. Apply a soft vignette effect in post-production to draw focus to the center, and enhance the warmth and saturation of colors to invite viewers to immerse themselves in this idyllic landscape.