The vivid color appearance of laser-induced periodic surface structures (LIPSS) has received intense research interests. The vibrant structural color associated with the periodicity of LIPSS is normally concerned under bright -field illumination, while the colors of structures under dark-field illumination are commonly overlooked. In this paper, we report an image encryption method based on laser-induced dual-period grating structures in indium tin oxide thin films, exhibiting different colors under bright-field and dark-field illumination. Following the standard laser recipe by judiciously controlling the polarization, pulse energy and scanning speed, subwavelength period LIPSS can be fabricated. By controlling the space between the fabricated lines, another grating with a larger periodicity can be formed. Consequently, the dual-period grating structure displays different colors under bright-field and dark-field illumination depending on the laser recipe with different pulse energies and line spaces. Leveraging this effect, information can be encoded in the color image, which displays the same color appearance under bright -field illumination while revealing different colors under dark-field illumination has been demonstrated. Combing the flexibility and scalability of laser fabrication, we envisage the potential applications in anti-counterfeiting, pattern decoration, metasurface, etc.