I’m guessing the recruiter made a text post and then looked for an “eye-catching” surgical tool image to make the post stand out.
Why would they directly send you an image with a recruitment message? Because they were lazy and just copied their recruitment post from elsewhere?
In this context (IIRC) smart means “if this zip contains a single folder with contents, directly extract that folder, but if the zip contains files and/or folders, extract all that to a new folder named the same as the zip file”.
Some people zip folders while some people zip the files in a folder. Smart extraction just handles both automatically.