1. A method comprising: obtaining a compressed plenoptic image generated by compressing an original plenoptic image; obtaining a refocusing parameter; obtaining residual data corresponding to difference between first refocused image and second refocused image, wherein the first refocused image is generated from the original plenoptic image using the refocusing parameter and the second refocused image is generated from a decompressed plenoptic image using the refocusing parameter, the decompressed plenoptic image being generated by decompressing the compressed plenoptic image; outputting data comprising the compressed plenoptic image, the residual data and the refocusing parameter.