Disclosed in the present invention are a method for encoding/decoding an image and a device for same. Particularly, a method for decoding an image may comprise the steps of: parsing the weight value (w) of a loop filter from a bitstream outputted from an encoder; applying the loop filter to an image obtained by using a prediction signal and a differential signal; and generating a recovered image and a reference image by performing the weighted sum of the recovered image before the loop filter is applied and the recovered image after the loop filter is applied, based on the w.