Are you using Internet Explorer or Firefox or something else?
Firefox remembers last folder browsed to.
Internet explorer 5.5+ shoudl remember it too, however if you are using Windows 98 as an operating system, no version of Internet Explorer will allow that, it's a limitation of the OS.
So If you are on Win98, I would try Firefox, everyone knows Internet Explorer sucks anyway, so get firefox here, it rules:
http://www.getfirefox.com, I hope it works on win98 I don't have the time to setup a VM for you and test, plus, maybe consider getting an operating system from the last 8 years, they have moved on quite a bit, I personally would recommend XP at this time, or windows 2000 if you have older hardware, or Vista if you really want to be slung into the future (need more powerful hardware, ask here if need advice).
An alternative which could make it easier using IE on win98 would be to create shortcuts from My Documents so you can quickly click those when it starts in My Documents, look here to do shortcuts:
http://www.computerhope.com/issues/ch000739.ht m
Also, doesn't flickr have some kind of uploading utility? I don't use it but if you use there proper uploader, you will probably find it more useful and quicker to navigate with.