This document presents a study on using discrete wavelet transform (DWT) for image steganography. DWT is applied to both the cover image and secret image. The secret image is embedded into the wavelet coefficients of the cover image. Arnold transformation and a private key are used to further encrypt the secret image for increased security. Experimental results on test images show that the proposed method achieves good visual quality for the stego-image, with PSNR values exceeding 36 dB. The method can hide secret data in both color and grayscale images. Future work may explore using different wavelet transforms or encryption techniques.