Searx's Science only search will search 10 or so engines dedicated only to science! This will leave out Wikipedia though. It is a metasearch engine. Find instances here. https://asciimoo.github.io/searx/user/public_instances.html https://stats.searx.xyz/
I think we still need more information about your server and requirements, but the most straight forward way of updating a file on a web server is FTP.
Point the FTP server to folder that is used by the web server to serve the image. Most hosting providers will offer some sort of FTP solution.
On your client machine rename your local file to be the same name ...