public static boolean isImage(String suffix) {
        if (null != suffix && !"".equals(suffix) && suffix.contains(".")) {
            String regex = "(.*?)(?i)(jpg|jpeg|png|gif|bmp|webp)";
            return isMatch(regex, suffix);
        }
        return false;
    }
@Test
    public void testIsImage(){
        Assert.assertEquals(true, PatternKit.isImage("a.png"));
        Assert.assertEquals(true, PatternKit.isImage("a.jpeg"));
        Assert.assertEquals(true, PatternKit.isImage("g.gif"));

        Assert.assertEquals(false, PatternKit.isImage("ggif"));
        Assert.assertEquals(false, PatternKit.isImage("g.txt"));
    }