align="top"

positions the top of the image with the top of the current text line. User agents vary in how they interpret this. Some only take into account what has occurred on the text line prior to the IMG element and ignore what happens after it.

align="middle"

aligns the middle of the image with the baseline for the current textline.

align="bottom"

is the default and aligns the bottom of the image with the baseline.

align="left"

floats the image to the current left margin, temporarily changing this margin, so that subsequent text is flowed along the image's righthand side. The rendering depends on whether there is any left aligned text or images that appear earlier than the current image in the markup. Such text (but not images) generally forces left aligned images to wrap to a new line, with the subsequent text continuing on the former line.

align="right"

floats the image to the current right margin, temporarily changing this margin, so that subsequent text is flowed along the image's lefthand side. The rendering depends on whether there is any right aligned text or images that appear earlier than the current image in the markup. Such text (but not images) generally forces right aligned images to wrap to a new line, with the subsequent text continuing on the former line.

Note that some browsers introduce spurious spacing with multiple left or right aligned images. As a result authors can't depend on this being the same for browsers from different vendors. See BR for ways to control text flow.

<IMG ALIGN="left|right|top|texttop|middle|absmiddle|baseline|bottom|absbottom">

The additions to your ALIGN options needs a lot of explanation. First, the values "left" and "right". Images with those alignments are an entirely new floating image type. A ALIGN=left image will float down and over to the left margin (into the next available space there), and subsequent text will wrap around the right hand side of that image. Likewise for ALIGN=right the image aligns with the right margin, and the text wraps around the left.

The rest of the align options are my way of trying to correct for the errors I made when first implementing the IMG tag, without destroying the look of existing documents. ALIGN=top does just what it always did, which is align itself with the top of the tallest item in the line. ALIGN=texttop does what many people thought top should do which is align itself with the top of the tallest text in the line (this is usually but not always the same as ALIGN=top). ALIGN=middle does just what it always did, it aligns the baseline of the current line with the middle of the image. ALIGN=absmiddle does what middle should have done which is align the middle of the current line with the middle of the image. ALIGN=baseline aligns the bottom of the image with the baseline of the current line. ALIGN=bottom does just what it always did (which is identical to ALIGN=baseline but baseline is a better name). ALIGN=absbottom does what bottom should have done which is align the bottom of the image with the bottom of the current line.