0.5's installer is a little over half the size of Mozilla 1.0 (~6Mb vs. ~11Mb, for the Win32 versions, both from 2002) which fits with my recollection that it was noticeably faster to download than Mozilla (on, say, Dial Up). I wanna say the on-disk install footprint saw an even bigger difference, but I don't have a great way to test that out quickly. I think we'd definitely class a browser [edit: a modern browser, that is, I'm making the comparison to illustrate that 5Mb wasn't a small difference back in 2002] with an install size a little over half that of Chrome's as notably lighter-weight—though, sure, they did get there largely by just cutting stuff out.
You're probably[1 EDIT] right that I'm mis-remembering Opera's download size. I recall it feeling heavier in use, but that was probably something to do with the feel of its particular (non-native) UI, and maybe the extra system resource strain from loading and displaying banner ads for the ad-supported version (there were still some really weak computers in wide use in 2002).
[1] I only wrote "probably", originally, because I didn't bother to verify it—not because I don't believe you on that point. I didn't express that very well.
You're probably[1 EDIT] right that I'm mis-remembering Opera's download size. I recall it feeling heavier in use, but that was probably something to do with the feel of its particular (non-native) UI, and maybe the extra system resource strain from loading and displaying banner ads for the ad-supported version (there were still some really weak computers in wide use in 2002).
[1] I only wrote "probably", originally, because I didn't bother to verify it—not because I don't believe you on that point. I didn't express that very well.