Remove the small tick in front of the file extension of the hidden known type, and click OK to display the full name of the file, so as to judge whether it meets the requirements of the server. There are many reasons for uploading files, such as the file is too big, the file is too small, the file extension is wrong, and so on. You need to check the source program to see what the requirements are for uploading files. Maybe your file format is really incorrect. Generally, they require that the picture should not be too big, and the format is generally jpg.gif Your picture will be OK after PS processing.