Method for encoding and decoding images, and device using same

A method for inter prediction performed by a decoding apparatus, comprising:

• receiving mode information on an inter prediction of a current block, wherein the mode information includes merge flag information indicating whether an inter prediction mode for the current block is a merge mode;
• deriving merge candidates of the current block based on neighboring blocks of the current block;
• selecting a merge candidate from the derived merge candidates;
• deriving a motion vector of the current block as to be equal to a motion vector of the selected merge candidate;
• and
• generating a prediction sample of the current block based on the motion vector of the current block,
• wherein the neighboring blocks includes a left neighboring block, an upper neighboring block, an upper-right corner neighboring block, an upper-left corner neighboring block, and a lower-left corner neighboring block of the current block.