Ah, didn't know JPEG blocks were consistently 8x8. But I'm assuming storage size of each block is variable-length? BMP wouldn't be decodable either; header get

Ah, didn't know JPEG blocks were consistently 8x8. But I'm assuming storage size of each block is variable-length? BMP wouldn't be decodable either; header gets mangled, right? This is a some kind of rendering of the cipher text. But in the 'block cipher on simple bitmap' case, the blocks map well to pixels; with any compressed format, that wouldn't be true.