Picture updating method and device

The invention discloses a picture updating method and device, and the specific implementation scheme is as follows: responding to a received application loading instruction, generating a first picture list corresponding to each picture identification code in a sandbox directory; when a picture loading condition is met, downloading a picture corresponding to the picture link into a sandbox, and storing a picture identification code corresponding to the picture link into a sandbox directory; when the picture resource of the sandbox is greater than a first preset value, traversing a sandbox directory, and generating a second picture list corresponding to each picture identification code and each picture time; traversing the second picture list; when the current picture identification code in the second picture list does not exist in the first picture list, compressing a target picture corresponding to the current picture identification code to generate a compressed picture; and on the basis of the compressed pic