Image replacement decision grid

Method	Support				read by Screenreader	Text selectable	Image printable	When to use
	CSS enabled		CSS disabled
	Images enabled	Images disabled	Images enabled	Images disabled
<img>	Image	Text [1]	Image	Text [1]	Yes	? [2]	Yes	when the Image is actual content
<Object> [6]	Image (or anything else)	Fallback Content	Image (or anything else)	Fallback Content	? [6]	No	Yes	When the image is content but needs to be described with complex markup if it is unavailable. Support?
cover up ~~Andrew~~ [5]	Image	Text	Text	Text	Yes	Yes	No	decoration
Phark, Leahy/Langridge	Image	Nothing	Text	Text	Yes	Yes	No	decoration, if image needs to be transparent or markup can't be changed
CSS2 :before	Image	Text	Text	Text	Yes	Yes	No	(only works in Opera7 and upcoming Safari, degrades nicely, support may grow soon)
CSS3 Content-Property [4]	Image	"Image"	Text	Text	Yes [3]	No	Yes	(only works in Opera 7, degrades nicely, relies on CSS3)
FIR	Image	Nothing	Text	Text	No	No	No	never, actually, convert to this

[1]: Safari will not show alt-text when images are disabled
[2]: Opera does not allow alt text to be selected. I'd consider that a bug in Opera. I've not tested it in other browsers
[3]: There is no Screenreader that supports CSS3
[4]: Can be used in addition to the other techniques to provide multiple backgrounds or to provide printable images with CSS
[5]: Here is a testcase Here is a more complex testcase that shows some problems with multiple layers
[6]: I do not know how browsers other than Opera 7.5 handle this