Multimedia data, nowadays, needs high levels of security as it is widely transferred over various networks. One of the newly-invented and most attracting safety-raising strategies is the chaos-based cryptography. This paper examines the competence of an algorithm for image encryption that uses a double-chaotic logistic map equation. The algorithm produces two sequence keys (K1 & K2) in two phases. First, an encrypted key is generated through a process of K1 being XORed with K2. The new key is later XORed with the original image in the second phase. We used Matlab tool to compare the performance of the proposed algorithm between the original and encrypted images by computing Histogram, Correlation and MSE (Mean Square Error). The results show much flatter and more uniform histogram plot with high values of MSE compared to images produced by one logistic map. Also, the correlation between adjacent pixels is about 0; no relation at all between the two image versions. Hence, the proposed algorithm improves the encoding efficiency compared with one logistic map.