Design in web development (from the English "design" - to plan, develop, create a sketch) is not just a beautiful picture. A designer is responsible for the layout, for a user-friendly, understandable, and accessible website interface, while illustrations and attractive images are created by an illustrator.
Design is the art of arranging and presenting materials on a page in such a way that users don't have to struggle to find the information they need, whether it's a dozen links or numerous informational blocks and news, including typography and graphics work.
Development implies creating a layout for a specific purpose, meaning that there should be a solution that meets the set objectives. For example, it's unlikely that a photo of a mobile phone store interior would be appropriate in the header of a pizza restaurant's website, even if their employees were caught having pizza for lunch.