Jim Tinsley, The Project Gutenberg FAQ 2002
“ Make your HTML as simple as possible. HTML is an evolving standard, and one that may be completely obsolete in the long term. Use of advanced features may just mean that your version will be obsolete or unreadable that much faster.6. Recommendation: ImagesImages included with your HTML should be in a format that Web browsers can read: GIF, JPEG or PNG. Images should be edited for high quality in a reasonably small file size. Make the best decision you can concerning the image size and placement in the text. ”
