Pieman - Figluvah advice works excellent and its simple.
I run XP as well with the updates on this old machine.
Download the power tools and it click it to self install -
Upload your picture to hardrive right from your camera as is.
Right click your picture and click resize -small/medium/large - time it takes is mere seconds to resize.
You can rename file to the name of fig just add .jpg at end of file if you choose.
It makes file size under 1mb and will easily upload to forum as a thumbnail ,the reader then simply clicks on your picture to blow it up.
Plus it saves Jon the moderator of this forum a lot of space .
I used Photobucket and this way is faster and easier for XP systems in my humble opinion.