First, open Baidu Post Bar and enter the signature setting window, as shown below.

In this window, you can click Add a set of signature files or you already have a signature file, and you can edit and modify it.

Second, after clicking "Add a set of signature files", a drop-down list will appear. In the picture link column, you can see the following tips: Post the bar for reference only, and the picture takes up space; In other words, you can only refer to the picture links in the post bar and the picture links in the space.