The <img> tag adds images to a webpage. The "src" in the <img> tag identifies the source of the image (ex. Img.jpg or a web link). The "alt" in the <img> tag identifies what text should appear on the web page in case the image doesn’t load, and the "width" and "height" identify the width and height in pixels of the image. However, "alt", "width", and "height" are not necessary for displaying the image.
The <iframe> tag makes videos appear in your webpage. The "width" and "height" of the <iframe> tag specify the size of the video in pixels, while the "src" identifies the source of the video.