How to submit uploaded images and scale them to a specified folder

When submitting an image on a php page, how to scale the image and keep only the scaled image? ? ?

Reply content:

When submitting an image on a php page, how to scale the image and keep only the scaled image? ? ?

First get the image from the uploaded file, and then use PHP's GD library to scale the image. After getting the scaled image, copy it to the specified folder.
In this operation process, it is a bit difficult to zoom in and out of pictures. There are functions/classes written by others on the Internet, such as php class-resizeimage class-picture generation thumbnails