1. A system for rendering an image using a light field image file, the system comprising: a processor; and memory containing a rendering application and a light field image file; wherein the light field image file is structured using the JPEG File Interchange Format (JFIF) and comprises: an encoded image; and metadata describing the encoded image stored within an application marker segment within the light field image file, where the metadata can be utilized to post-process the encoded image; wherein the metadata comprises a depth map that specifies depths for pixels in the encoded image; and wherein the rendering application directs the processor to render an image having at least one focus area at a particular depth by applying post processing to the encoded image using metadata contained within the light field image by: locating the encoded image within the light field image file by locating a start of image marker within the light field image file; decoding the encoded image; locating the metadata within the light field image file; and processing the decoded image by modifying the pixels of the decoded image based on the depths of the pixels indicated within the depth map to create a rendered image by applying a depth based effect to the pixels of the decoded image.