A method and system is disclosed for generating a caption relative to a three-dimensional image. An image forming apparatus having a gas purifying apparatus, and a method of purifying gas of the image forming apparatus are also provided. A transparent resin containing a wavelength converting material is provided on a reflecting surface of a base member such as a case, a board and a lead frame. A fitting ditch between the inner surface of the cover and the thin plate wall is provided on the thin plate wall. Accordingly, a wearer’s foot in the shoe can be vented.