Hephaestus in his forge, by Andrea Mantegna. 

The Yorck Project: 10.000 Meisterwerke der Malerei. 
Wikipedia

In the foreground, Hephaestus stands naked except for a red cape blowing in the wind, in front of his cave.  To his left is an anvil and some rods of iron. To the right is the forge with fire burning and a crucible for molten metal.  At the foot of the forge is a bag used for a bellows.