Capturing post-snapshot quiescence writes in an image backup. In one example embodiment, a method for capturing post-snapshot quiescence writes in an image backup may include taking a first snapshot of a source storage at a first point in time, identifying a first set of block positions of blocks that are allocated in the source storage at the first point in time, identifying a second set of block positions of blocks that are written to the first snapshot during post-snapshot quiescence of the first snapshot, resulting in a first quiesced snapshot, calculating a third set of block positions by performing a Boolean OR operation on the first set of block positions and the second set of block positions, and copying blocks in the third set of block positions from the first snapshot to a full image backup.