How can I reduce the image size of a PNG file

[ying lam]

Hi,

I am using the following code to convert an image to a PNG file:

   
                 //Read the url to a BufferedImage
BufferedImage image = ImageIO.read(new URL(url));

//Create a file for the output
File output = new File("/home/ying/image.png");
 
//Write the image to the destination as a PNG
ImageIO.write(image, "png", output);
 

I would like to know how can I reduce the file size of the converted file.
I read there is a trick which can reduce the color map of the result image without losing much image quality.

Can you please tell me how can I do that in java?

Thank you.

[Ulf Dittmer]

There's example code that shows how to compress an image to a JPEG here. It's possible that it works out of the box with PNGs as well (I'm not sure about the algorithms PNG uses), or -worst case- you can write a JPEG in the desired quality/compression, read it back into memory, and then write it as a PNG.

[ying lam]

Thank you.