Writing papers and quoting pictures on the Internet generally does not constitute infringement.

Baidu is just a search. To find the original source, try to contact the picture author, contact the author, indicate the intention, get the author's consent, and indicate the source and original author when quoting.

Even if you can't contact the original author, you should find the information of the original author of the picture. When quoting a paper, please indicate the name of the original author. Don't use the name of Baidu. Baidu didn't provide anything, just help you search.

It depends on what kind of paper you write. Generally, infringement will not be involved.