Yes, or by extending the pixels on the edge out forever. The question is which one is more effective for compression; it turns out doing that for individual blo

Yes, or by extending the pixels on the edge out forever. The question is which one is more effective for compression; it turns out doing that for individual blocks rather than the entire image is better. (With mirroring things could happen like the left edge of the image leaking into the right, and that'd be weird.)