A subdirectory is the same thing as a folder. Create subdirectories to organize your HTML files by topic. Keep names short and descriptive Give your files and subdirectories short but descriptive names with no spaces, and always use lower case only. Remember, these names appear in your URL, which are case sensitive. Put cross links to all your major pages at the bottom of all major pages.
Graphics are one reason for the interest in the Web by both publishers and readers.
Definitely include graphics. The Web version of a document should contain the same graphics the printed version does. However, do not overuse graphics. Blinking text and other decorations are only distractions that get in the reader's way. Background colors and textures should be used cautiously and sparingly, because of additional download time.