ACS Style image citation
From the ACS Style Guide, regarding the correct format for citations of websites (quote slightly reformatted):

Recommended format for general web sites:
Author (if any). Title of Site. URL (accessed Month Day, Year), other identifying information (if any). Use the title found on the Web site itself; add the words “Home Page” for clarification when needed.
...
ACS Publications Division Home Page. http://pubs.acs.org (accessed Nov 7, 2004).
Chemical Abstracts Service. STN on the Web. http://stnweb.cas.org (accessed Nov 7, 2004).
International Union of Pure and Applied Chemistry Home Page. http://www.iupac.org/dhtml_home.html (accessed April 24, 2005).
...
Recommended format for documents retrieved from institutional or agency web sites:
Author 1; Author 2; Author 3; etc. Title of Document, Year. Title of Site. URL (accessed Month Day, Year). If an article is contained within a large and complex Web site, such as that for a university or a government agency, the host organization and the relevant program or department should be identified before giving the direct URL of the article and accession date.
Chou, L.; McClintock, R.; Moretti, F.; Nix, D. H. Technology and education: New wine in new bottles: Choosing pasts and imagining educational futures, 1993. Columbia University Institute for Learning Technologies Web site. http://www.ilt.columbia.edu/publications/papers/newwine1.html (accessed Aug 24, 2000)

In your case, I would considering citing it as a document, so it would become:

KGM007, Opium pod cut to demonstrate fluid extraction1, 2006, Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Opium_pod_cut_to_demonstrate_fluid_extraction1.jpg (accessed Feb 17, 2018)

You could cite it as a web page - that would look like this:

KGM007, File:Opium pod cut to demonstrate fluid extraction1.jpg - Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Opium_pod_cut_to_demonstrate_fluid_extraction1.jpg (accessed Feb 17, 2018)

In your citation, you gave the name of the site, not the title. The title (as defined by the HTML title tag) is what shows in the top of your web browser when you visit the page:
If you intend to submit this for publication, the publisher should check and confirm the format during production anyhow.