The present application discloses image coding and decoding methods and apparatuses, and a storage medium, relates to the field of image coding and decoding technologies, and helps to improve coding and decoding efficiency. An image decoding method includes: parsing a code stream to obtain a first syntax element, where the first syntax element includes an index of a target prediction mode of a to-be-decoded unit; determining the target prediction mode from an index table based on the index of the target prediction mode, where the index table includes correspondences between indexes of multiple prediction modes and the multiple prediction modes; reconstructing the to-be-decoded unit based on at least the target prediction mode to obtain a reconstructed block.