Health-related websites provide valuable information, resources, and support for individuals seeking to improve their health and make informed decisions about their well-being. Graphical content makes websites visually appealing and helps create a positive first impression. Relevant and high-quality graphical content can immediately capture visitors' attention and make the website more attractive and memorable. However, irrelevant graphical content on web pages also indicates poor readability, distracting readers from the text's focus. This paper's primary objective is to assess the effect of irrelevant or low-quality graphical content on the readability of a health-related website. The relevance of graphical content on a website was computed using a tool proposed in our previous research. A user study comprised of end-user evaluation and heuristic evaluation by readability experts was conducted using a variety of question categories. Both evaluation methods yielded comparable results, confirming that the pertinent graphical content enhances the readability of the web page. This research will help web designers improve the quality of their websites by contemplating only the relevant content of a website rather than relying on expert opinion.