Because in the past, the picture addresses of Baidu photo albums all started with hiphotos (not counting http:// lowercase letters. ), and the signature file only recognizes addresses that may start with this. But now that the address is changed to the beginning of picphotos, Baidu may not recognize it, which is why it can't be saved.

Solution: Change picphotos in the picture link address to hiphotos, and it will generally work.