512*384 =  4:3 = 196608

480*480 =  1:1 = 1.00 = 230400
540*432 =  5:4 = 1.25 = 233280
560*420 =  4:3 = 1.33 = 235200
594*396 =  3:2 = 1.50 = 235224
600*400 =  3:2 = 1.50 = 240000
624*384 = 13:8 = 1.63 = 239616  special
640*375 =      = 1.71 = 240000  special
640*360 = 16:9 = 1.78 = 230400

1280x720
1920x1080
3840x2160


mogrify -crop 1844x1080+38+0 -resize 640x375 -format jpg -quality 95 *.jpg


mogrify -resize 1920x1080 -quality 95 -format jpg *.png
ls -v | cat -n | while read n f; do mv -n "$f" "$n.jpg"; done

-crop 40x30+10+10
-gravity Center -crop 40x30

mogrify -crop 3753x2111+44+0 -resize 1920x1080 -format jpg -quality 95 *.png


KageYume:
mogrify -crop 3776x2124+32+0 -resize 1920x1080 -format jpg -quality 95 *.png   # 4*9=36, 4*16=64