七牛图片透明处理

 原七牛图片地址：
https://imageservice-cdn.etledu.com/ZheJiangEmergencyTrain/zjytpx/Test/TrainApplets/IdentityCard/2024/5/21/b55200445588498eb09e14999c833696.png

后片接 ?imageMogr2

https://imageservice-cdn.etledu.com/ZheJiangEmergencyTrain/zjytpx/Test/TrainApplets/IdentityCard/2024/5/21/b55200445588498eb09e14999c833696.png?imageMogr2 

变成透明的

https://imageservice-cdn.etledu.com/ZheJiangEmergencyTrain/zjytpx/Test/TrainApplets/IdentityCard/2024/5/21/b55200445588498eb09e14999c833696.png?imageMogr2/border/10x10/bordercolor/cmVk