This tag can be very useful, it is then disappointing to know then that as it was first used in later versions of HTML, then it would be cheating to use this tag.
PNG: The PNG file type is very useful format outside of making a website that is WorldWideWeb-compatible, not only does it allow transparency, but it also supports lossless data compression - that is a fancy way of saying that (let's say) you're making a drawing, once you save the image in the PNG format, then no (noticeable) quality will be lost. The initial release for this format was 1996, so six-ish years after the WorldWideWeb browser was made.
SVG: The Scalable Vector Graphics or just SVG is what is known as an XML-based vector image format for two-dimensional graphics with support for interactivity and animation. Long way of saying that it uses vectors, rather than pixels. That's also a long way of saying that it means that an SVG image can be easily be made bigger or smaller without losing any quality or becoming blurry. The file format first came to be in 2001.
WebP: Seemly the new kid on the block, WebP is an interesting subject, as it uses both lossy and lossless compression. It is currently being developed by Google of all people, technology that was acquired with the purchase of On2 Technologies, who were known as The Duck Corporation. Release in 2010.
GIF: Perhaps one of the best known image format on this list, the GIF is a bitmap image format that was developed by the first major commercial online service provider in the United States, CompuServe, in 1987. The format is unique as it is one of the only image types that all an animation medium. The format can store multiple images in one file, allowing an image to move, as if it was a silent film.
PCX: PiCture eXchange is an image format developed by the now-defunct ZSoft Corporation, PCX became one of the first widely accepted DOS imaging standards (for example, in id Software's Doom, screenshots are saved in this format). The format first came out in 1985, with its last update in 1991; because of this, a lot of modern operating systems no longer natively support the format.
Out of all of the three formats, TIFF *might* be the best for images you don't need to be transparent vMIGHT BE WRONGv
What you can use
Normally a very basic but valid website's source would look something like this, everything checks out;
However, as the HTML and HEAD tag had not yet been invented, then a website that is valid only in HTML1 would look like this. . .
*dies on the inside*
Copyright 2019, Clive "James" Python, firstname.lastname@example.org Attribution-NonCommercial-ShareAlike 4.0 International