Huh, why would that be? Drawing a round corner is in fact more complex than drawing a square one, but surely for a few dozen rounded corners the number of additional CPU cycles spent pales in comparison to things like anti-aliased font rendering, calculating CSS box model layouts, decompressing gzipped contents and the myriad of other tasks that a browser has to perform during loading and rendering of a web site nowadays.

For 4 rounded corners you probably need to download 4 images. Thats 4 extra connections to the server to connect to, download, process.

It isn't the processor time that is taking longer its the transfer time.

Most modern browsers (all but IE I believe) will let you round corners with CSS. An extra line or so of CSS is hardly much of a transfer overhead.

I believe current thinking (on non-enterprise sites anyway) is to let the IE people have their square corners, and those on new browsers get all the curvy goodness.

Yes, that is why I added the probably. The vast majority of rounded corners I see are still done with images however.

Not anymore you don't.

I don't doubt that she said this, but I can't find the quote by Googling, and I would love to see it for myself, in context. Can you provide a link? Thanks!