PNG

Pngs are currently not supported by IE - we are led to believe that IE 7 will support them - so if you use pngs then you need to send IE an alternative version of the image that it does accept.

Or better still, check out: http://homepage.ntlworld.com/bobosola/index.htm

DE

Thank you very much

PNG's work great in IE and Mosaic; for certain purposes.

http//beta-154104.server1.dotnetsandbox.net/Oil.aspx

These three graphics are miniscule in size; less than 4K each.

And that is the single greatest advantage for this application.

Telling Excel to produce these in .GIF or .JPG format instead of .PNG results in huge files of 50K+ with zero benefit-added.

So, the easy-to-answer question for me was did I want to deliver 50K per pic or 4K per pic?

Actually IE/Win does support png but it is turned off by default. (something like that). Do a search for Sleight.js for more information.

IE6/Win does support PNG, what it doesn't supports is the Alpha chanel (transparency) on PNG.
With PNG you can set different levels of transparency, while with GIF you can only set transaprency on or off. It's also great for pictures without quality loss and in small size. So we can say PNG brigns the best of GIF and JPG worlds in one format.

AlphaImageLoader Filter Internet Development Index

Displays an image within the boundaries of the object and between the object background and content, with options to clip or resize the image. When loading a Portable Network Graphics (PNG) image, tranparency—from zero to 100 percent—is supported.

http//msdn.microsoft.com/workshop/author/filter/reference/filters/alphaimageloader.asp

Actually, it does support alpha channel with sleight.

Check here with IE/Win: http://www.eaglesnestministries.com/proof.html

(5.5 and up, I think)

Try a resize.

DE

Excellent link, very easy to understand - thanks!

Yeah but that's cheating

I can;t see how that's possibly a good way to achieve it - I have two broken image placeholder boxes over the image, not to mention a JavaScript error.

Your browser is busted.

Seriously though, it was my fault...the broken image box over the image should be gone now.

What is the javascript error you receive?

I dont know - when I tried to view the JS error through IE it busted my PC.

This page contains only .GIF's and succeeds with Internet Explorer 6 XPSP2:

http://beta-154104.server1.dotnetsandbox.net/Pixel%20Dust.aspx

This same page contains only .GIF's and would be successful with Mosaic 5.0 were it not for the failure of ALT tag display:

http://beta-154104.server1.dotnetsandbox.net/Pixel%20Dust.aspx

This page contains .PNG's and .GIF's and succeeds with Internet Explorer 6 XPSP2:

http://beta-154104.server1.dotnetsandbox.net/Pixel%20Dust%20With%20PNGs.aspx

This same page fails with Mosaic 5.0 in terms of PNG display and ALT tag display:

http://beta-154104.server1.dotnetsandbox.net/Pixel%20Dust%20With%20PNGs.aspx

Incidentally, Internet Explorer 6 XPSP2 Help includes the following text: "Based on NCSA Mosaic. NCSA Mosaic(TM); was developed at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign".

Caveat: These two pages do not successfully pass html testing criteria pointed at by Tony's note: http://www.htmlhelp.com/tools/validator/

Nonetheless, the page does displays flawlessly in Internet Explorer 6 XPSP2.

The posts on this topic are about a year old, and I'd like to know if these comments still valid.

If I use a png file, do I need to provide an alternative for IE? Can I do that without using javascript?

Thank you,
Susan

IE7 supports PNG Alpha Transparency, but IE7 is only going to be a forced upgrade on WinXP SP2.

So you're still gonna have millions of users on Win2000 and 98, using IE6 and below.