java压缩图片，但获取“未知压缩方法”

Question

我运行了一个java chatgame客户端，它会在聊天中显示图片之前加载图片

我确实通过Yahoo Smush压缩了我们在聊天游戏中使用的所有图片。但在Java控制台中出现此错误后：

java.util.zip.ZipException: unknown compression method
    at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:147)
    at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:237)
    at sun.awt.image.PNGImageDecoder.produceImage(PNGImageDecoder.java:344)
    at sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.java:246)
        at sun.awt.image.ImageFetcher.fetchloop(ImageFetcher.java:172)
    at sun.awt.image.ImageFetcher.run(ImageFetcher.java:136)
Uncaught error fetching image:
java.lang.ArrayIndexOutOfBoundsException
    at java.lang.System.arraycopy(Native Method)
    at sun.awt.image.PNGFilterInputStream.read(PNGImageDecoder.java:810)
    at java.util.zip.InflaterInputStream.fill(InflaterInputStream.java:221)
    at java.util.zip.InflaterInputStream.read(InflaterInputStream.java:141)
    at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
    at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
    at sun.awt.image.PNGImageDecoder.produceImage(PNGImageDecoder.java:346)
    at sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.java:246)
    at sun.awt.image.ImageFetcher.fetchloop(ImageFetcher.java:172)
    at sun.awt.image.ImageFetcher.run(ImageFetcher.java:136)

但现在我已经在photoshop中打开了所有图片并再次保存，但它占用了超过20MB的磁盘空间，所以我的问题是：

如何正确压缩所有图像而不与java压缩冲突？ 有网站吗