Since the keyword here is multi-platform I think using different icon themes for each platform would be a great solution.
Many platforms already have default icons for most of the "tasks", so that should make it easier to achieve.
Take a look at latest Firefox! It looks great!
You sure don't want to make a multi-platform application have the same "sparky" look on different platforms, aim for smooth and neutral.
For example, Clo
's sample might look good on windows 95 and maybe 98/ME at 800x600, but what about XP? Or even Vista, Mac or KDE 4?! It'd look grose on those!
No one wants to taint their loved desktop environment with alien looking applications. That's one reason that made quit using Wine'd XnView on Linux.
I'm not much of a Vista user but thibaud
's image looks great.
16x16 is enough. I'm on a 15.4" at 1280x800 screen and they look great and I can totally figure what they represent. They have to be tiny and briefly descriptive. Take a look at website's favicons, forum emoticons, icons on system tray, menu icons on the majority of the applications!
There are standards and guidelines and we must follow them if we don't want to be neglected.
I was a intensive user of XnView on Windows but couple of years ago I started migrating to Linux and since then I just surrendered to several native linux applications instead of "emulating"the all-in-one XnView.
I still visit the forum to get some updates on the much expected MP version.
Please don't ruin it for us (non windows users that don't have a decent alternative to window's XnView).