Converting transparent gif / png to jpeg using java

Question

I'd like to convert gif images to jpeg using Java. It works great for most images, but I have a simple transparent gif image: Input gif image http://img292.imageshack.us/img292/2103/indexedtestal7.gif [In case the image is missing: it's a blue circle with transparent pixels around it] When I convert this image using the following code: ``` File file = new File("indexed_test.gif"); BufferedImage image = ImageIO.read(file); File f = new File("indexed_test.jpg"); ImageIO.write(image, "jpg", f); ``` This code works without throwing an Exception, but results an invalid jpeg image: [In case the image is missing: IE cannot show the jpeg, Firefox shows the image with invalid colors.] I'm using Java 1.5. I also tried converting the sample gif to png with gimp and using the png as an input for the Java code. The result is the same. Is it a bug in the JDK? How can I convert images correctly preferably without 3rd party libraries? UPDATE: Answers indicate that jpeg conversion cannot handle transp…

Accepted Answer

For Java 6 (and 5 too, I think):

```
BufferedImage bufferedImage = new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_INT_RGB);
g = bufferedImage.createGraphics();
//Color.WHITE estes the background to white. You can use any other color
g.drawImage(image, 0, 0, bufferedImage.getWidth(), bufferedImage.getHeight(), Color.WHITE, null);
```

Converting transparent gif / png to jpeg using java

Solution

Problem