[kibwen]

That's an interesting Firefox logo you're displaying. Rather than featuring the generic "Planet Mozilla" globe, it appears to be using a map of Earth centered on Japan. The fox looks a bit sleeker as well.

For comparison, here's the official Firefox branding page: http://www.mozilla.org/en-US/firefox/brand/identity/

[prateekdayal]

I never noticed that :) Here is the icon set (free for commercial use) - http://www.iconfinder.com/search/?q=iconset%3Abrowsers

[notatoad]

the official icons for all the browsers have licenses that allow them to be used anywhere, as long as they are only used to refer only to their official product (i.e. you can use the firefox logo anywhere you want, as long as you only use it to mean firefox and not some other product)

IANAL, but i believe that creative reproductions like the ones you are using violate the trademark of the actual icon owner, and they certainly violate the branding guidelines of all the browsers in question.

Just use the official icons: it's clearer for your users, and it is what the browser vendors want you to do.