An image encryption method, an image viewing method, a system, and a terminal are provided. The image encryption method includes: editing an original image, saving the edited original image as a first image file; encrypting the original image to generate an encrypted data block; and, splicing the first image file with the encrypted data block to generate and save a partially-encrypted image file. The image viewing method includes: when determining that indication information used for indicating partial encryption process is carried in an image file, decrypting an encrypted data block, and displaying data of an original image obtained after decrypting successfully; herein, the partially-encrypted image file is formed by splicing the first image file and the encrypted data block, the first image file contains edited original image data, and the encrypted data block corresponds to encrypted original image data.