Image encoding/decoding method based on image transform, method for transmitting bitstream, and recording medium on which bitstream is stored

An image encoding method performed by an image encoding apparatus, the image encoding method comprising:

• transforming a picture based on any one of at least one candidate transform;
• and
• encoding the transformed picture in a bitstream,
• wherein the at least one candidate transform is a rotation transform or symmetry transform for the picture.

A method of transmitting a bitstream generated by an image encoding method, the image encoding method comprising:

• transforming a picture based on any one of at least one candidate transform;
• and
• encoding the transformed picture in a bitstream,
• wherein the at least one candidate transform is a rotation transform or symmetry transform for the picture.