Bueno hay una clase en Zinc llamada Image, estos son sus métodos:
Image.bmpToJpg() Converts a BMP image to a JPG image of the same name.
Image.bmpToJpgAdv() Converts a BMP image to a JPG image of the same name.
Image.bmpToPng() Converts a BMP image to a PNG image with transparency.
Image.getJpgSize() Returns the size of the JPG image file to an array.
Image.getSwfHeader() Returns the header information of a SWF movie.
Image.jpgToBmp() Converts a JPG image to a BMP image of the same name.
Image.jpgToSwf() Converts a JPG image to a SWF file of the same name.
Image.jpgToSwfSlideShow() Converts a sequence of JPG images to a single SWF slideshow.
Image.pngToSwf() Converts a PNG image to a SWF file of the same name.
Image.pngToSwfTransparent() Converts a PNG image to a SWF file of the same name with Transparency.
Image.setJpgSize() Resize's the JPG image and saves the output file to a BMP.