"Zotero is the only research tool that automatically senses content in your web browser, allowing you to add it to your personal library with a single click. Whether you're searching for a preprint on arXiv.org, a journal article from JSTOR, a news story from the New York Times, or a book from your university library catalog, Zotero has you covered with support for thousands of sites."
Why do I need to cite?
Citations represent the breadth and depth of research
Recognize the origins and basis for your arguments, findings, and conclusion
Recognize the work of scholars and practitioners before you
Identify the words, ideas, images, videos, and any content from somewhere else.
What should I cite?
Ok, so let's say you are sifting through dozens of images and need only one view of a precedent for the final presentation, Unless you captured or drew the image yourself, The answer is always, yes. Cite everything.