Pour boiling water on the back of the fold, pull it up and flatten it (remember not to burn the boiling water directly to the front picture, and be careful not to burn yourself). A conditional hair dryer can use hot air to blow.

When installing the scraper net, you must use force, and if possible, use tools such as pliers to install it.

If it is a light box picture, you must pull the edge of the picture hard to install and fix it. Turning on the light is equivalent to heating the picture, and the picture will naturally be flat in a few days.