I was wondering is it ok to use png's without fear of the dreaded red x?
Just as long as you don't use transparency you will be ok. IE6 and earlier can't handle it without using hacks which are a pain in the butt to use.
Older browsers don't know what a .png is.
Thanks for the clarification. I'll just stick to gif's then, thanks again
Use PNGs. The older browsers they are referring to aren't used anymore so you can safely ignore them. PNGs are superior to GIFs.
The difference is quality!...
PNG's look better, use transparency better but take more space.
Later versions of Internet Explorer have problems recognizing the PNG transparency but GIF transparency usually always shows, but its more pixelated.
Hope this helps
Depends on the situation. PNG file sizes are pretty good in my opinion and have higher quality. View the link below for fixing the alpha issues with IE6. FF and Safari will display the alpha just fine.
That work-around only works in cases where the PNG was displayed with an image tag, so don't expect alpha to work on images used as table cell backgrounds.