sips -Z 1400 input.jpeg -o output.jpg

sips - scriptable image processing system.
This tool is used to query or modify raster image files and ColorSync ICC profiles.
Its functionality can also be used through the "Image Events" AppleScript suite.

  Usages:
    sips [image-functions] imagefile ...
    sips [profile-functions] profile ...

  Profile query functions:
    -g, --getProperty key
    -X, --extractTag tag tagFile
        --verify
    -1, --oneLine

  Image query functions:
    -g, --getProperty key
    -x, --extractProfile profile
    -1, --oneLine

  Profile modification functions:
    -s, --setProperty key value
    -d, --deleteProperty key
        --deleteTag tag
        --copyTag srcTag dstTag
        --loadTag tag tagFile
        --repair
    -o, --out file-or-directory

  Image modification functions:
    -s, --setProperty key value
    -d, --deleteProperty key
    -e, --embedProfile profile
    -E, --embedProfileIfNone profile
    -m, --matchTo profile
    -M, --matchToWithIntent profile intent
        --deleteColorManagementProperties
    -r, --rotate degreesCW
    -f, --flip horizontal|vertical
    -c, --cropToHeightWidth pixelsH pixelsW
        --cropOffset offsetY offsetH
    -p, --padToHeightWidth pixelsH pixelsW
        --padColor hexcolor
    -z, --resampleHeightWidth pixelsH pixelsW
        --resampleWidth pixelsW
        --resampleHeight pixelsH
    -Z, --resampleHeightWidthMax pixelsWH
    -i, --addIcon
        --optimizeColorForSharing
    -o, --out file-or-directory
    -j, --js file

  Other functions:
        --debug           Enable debugging output
    -h, --help            Show help
    -H, --helpProperties  Show help for properties
        --man             Generate man pages
    -v, --version         Show the version
        --formats         Show the read/write formats