下载附件，得到图片

010跑一下模板，正常，没问题

送进Stegsolve，发现lsb隐写，数据分析发现zip文件

保存二进制文件为压缩包，解压，得到flag.txt

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

看到开头iVBORw0KGgoAA……猜测base64的png图片编码，直接解码，报错
找一张png图片转成编码看看，差了前面关键的几个字符

补上，再试试，得到flag

总结：不能光积累各种文件16进制标识符，还要适当积累各种总文件base64或其它格式编码后的标识符