According to various embodiments of the invention, improved downsampling techniques are employed, which can be applied to light field images and which preserve the ability to refocus (and otherwise manipulate) such images. Groups of pixels, rather than individual pixels, are downsampled; such groups of pixels can be defined, for example, as disks of pixels. Such downsampling is accomplished, for example, by aggregating values for pixels having similar relative positions within adjacent disks (or other defined regions or pixel groups) of the image. When applied to light field images, the downsampling techniques of the present invention reduce spatial resolution without sacrificing angular resolution. This ensures that the refocusing capability of the resulting light field image is not reduced and/or adversely impacted.