jpegtran

Perform lossless transformation of JPEG files. More information: https://manned.org/jpegtran.

• Mirror an image horizontally or vertically:
  jpegtran -flip {{horizontal|vertical}} {{path/to/image.jpg}} > {{path/to/output.jpg}}
• Rotate an image 90, 180 or 270 degrees clockwise:
  jpegtran -rotate {{90|180|270}} {{path/to/image.jpg}} > {{path/to/output.jpg}}
• Transpose the image across the upper-left to lower right axis:
  jpegtran -transpose {{path/to/image.jpg}} > {{path/to/output.jpg}}
• Transverse the image across the upper right to lower left axis:
  jpegtran -transverse {{path/to/image.jpg}} > {{path/to/output.jpg}}
• Convert the image to grayscale:
  jpegtran -grayscale {{path/to/image.jpg}} > {{path/to/output.jpg}}
• Crop the image to a rectangular region of width W and height H from the upper-left corner, saving the output to a specific file:
  jpegtran -crop {{W}}x{{H}} -outfile {{path/to/output.jpg}} {{path/to/image.jpg}}
• Crop the image to a rectangular region of width W and height H, starting at point X and Y from the upper-left corner:
  jpegtran -crop {{W}}x{{H}}+{{X}}+{{Y}} {{path/to/image.jpg}} > {{path/to/output.jpg}}