An image watermarking algorithm that aims to protect the region of interest (ROI) is proposed based on fractal dimension. The ROI in an image is determined by the user, and is mapped to the subband of wavelet decomposition. A visually significative watermark is scaled according to the size of the ROI. Embedding is completed by enforcing the relationship between the subband coefficients and approximate coefficients. The parameters and strength is determined according to the feature analysis to the image which is based on fractal dimension. Extraction is blind that requires neither the host image nor the original watermark. Experimental results show that this algorithm can robustly resist cropping, patching, and compression.