C # verify whether the image format is true

When uploading images, we need to limit the format and size of the images uploaded by users.

However, another scenario is to verify that the user has forged images that meet the requirements. In this case, the real format of the file must be verified.

C ++ can read a file into a two-step stream and use a single character segment, which is 255216 for example. jpg.

System. Io. binaryreader BR = new system. Io. binaryreader (Stream );

Of course, there are many mature and easy-to-use File Upload plug-ins that we can directly prepare and use, so we don't have to worry about these issues.