In this paper, we study the security of an image scrambling algorithm based on Space-Filling Curves (SFC). A random SFC is a pixel permutation that changes the scanning order without changing pixels values. Few attacks were reported in the literature. A ciphertext-only attack when a different scan is generated for each frame in the video was proposed. The success of this attack heavily depends on the statistics of the plain frame. In addition, scanning each frame with a different SFC is not adapted to compression as many compression algorithms exploit temporal redundancy. We revisit the security properties of this scrambling technique and propose an efficient and low-cost chosen-plaintext attack when the same SFC is used for each frame in the video.