php 如何保存 base64编码的图片

Question

在html页面中我是做了一个javascript签名功能，用户签名确认后，会生成下面的base64的字符串，然后我把它传给服务器php文件，到了这里我就不知怎么做了。我是想把它保存成jpg图片放在服务器上，服务器的系统是linux.[/color],紧急要用到，大家有用的回答我会给分的。
data:image/jpeg;base64,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Answer 1

用base64_decode解码 再用file_put_contents创建图片$data=base64_decode('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');
file_put_contents("img.jpeg",$data);