Print on paper.
Physically cut out the pieces you want to send to remove.
Scan.
Still suspect that someone can undo this from data may have been accidentally steaganographed across non-deleted parts of the image.
Still suspect that someone can undo this from data may have been accidentally steaganographed across non-deleted parts of the image.
However, I wonder whether heavily compressing the redacted image would help remove any unwanted artefacts. But the best solution is probably to render the original file from scratch, without compression, before redacting the image.