Jeremy of all Trades Home » Blog article: Directory Recursing Thumbnail Generator

Put this script in a particular directory (or change the directory specified in startDir variable
and it will recurse through all sub-directories, creating thumbnails of the images (jpg, png, gif, or bmp).
If you change the deleteOriginal variable to true, it will delete the original image for you afterwards.

import javax.imageio.*
import java.awt.*;
import java.awt.image.*;

def startDir = new File(".")
def deleteOriginal = false
def thumbWidth = 200
def thumbHeight = 150

startDir.eachFileRecurse{file->
	if(file.name =~ /\.(JPG|jpg|PNG|png|GIF|gif|BMP|bmp)$/)
	{
		def imgType = file.name.replaceAll(/[^\.]*\.(JPG|jpg|PNG|png|GIF|gif|BMP|bmp)$/, "\$1")
		def imgPath = file.getCanonicalPath().replaceAll(/\.(JPG|jpg|PNG|png|GIF|gif|BMP|bmp)$/, "_Thumb.\$1")
		println("$imgType, $imgPath")

		//load each image
		img = ImageIO.read(file)
		println (file.name + " " + img.width + "x" + img.height)

		//output scaled thumbnail image
		width = thumbWidth
		height = thumbHeight
		if(img.width < img.height){width = thumbHeight; height = thumbWidth;}
		BufferedImage thumbImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics2D gThumbImg = thumbImg.createGraphics();
		gThumbImg.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
		gThumbImg.drawImage(img, 0, 0, width, height, null);
		ImageIO.write(thumbImg, "$imgType", new File(imgPath))

		if(deleteOriginal)
		{
			file.delete()
		}
	}
}