'-delete', '1--1', # static
'-trim',
'-background', 'white', '-layers', 'flatten', # opaque
+ '-auto-orient', # apply exif rotation
'-interlace', 'plane', # progressive
+ '-strip', '-taint', # omit metadata
+ '-sampling-factor', '4:2:0', '-colorspace', 'sRGB', # half chroma
'-resize', "${width}x${height}",
'-quality', '85%',
$source, "jpg:$target"