transform image to a square rounded thumbnail

convert.js

var fs = require('fs')
var spawn = require('child_process').spawn

var convertToSquare = spawn('convert', ['-quality', '1', '-', '-resize', '150x150^^', '-gravity', 'Center', '-extent', '150x150', 'PNG32:-'])
var convertToCircle = spawn('convert', ['-size', '150x150', 'xc:none', '-fill', '-', '-draw', 'circle 75,75 75,1', 'PNG32:-'])

var readFile = fs.createReadStream('image.png')
var writeFile = fs.createWriteStream('image-150x150-circle.png')

readFile.pipe(convertToSquare.stdin)
convertToSquare.stdout.pipe(convertToCircle.stdin)
convertToCircle.stdout.pipe(writeFile)

convertToSquare.stderr.pipe(process.stderr);
convertToCircle.stderr.pipe(process.stderr);