Don't know if this is any help Fred. I try and keep my camera set to a medium (to poor?

) setting to start with. I have Microsoft PicureIt - if you have this then this is how I do it.
If my pics are already on file, I open PictureIt and open my file and select the picture. Once you've opened the Pic, you can do all sorts with it (even improve in my case).
Once you have tweaked it, click on Format in the toolbar and, at the top of the drop-down menu is picture resize. Click on this and it will open at the L/H side of your pic.
I select cm (centimetres) and 28 (which is the number of pixels - I think - per cm).
Whichever is the largest measurement of picture - height or width - I reduce to around 21 to 23. Once thats done, click on "Done" at the bottom click on the X to exit and it will ask if you want to save the changes. Click on yes and thats your resized pic saved.
Go in to pictures and select the one you have reduced - right click and select properties. If the pic is less that the maximum dowload size you have cracked it.
If you haven't got Picture-It I'm sorry for wasting your time - and - if you find a better, easier way let me know
Mick
PS. I often just make folder for picture resizes and COPY any pics I want to alter - that way I still have the original in case I make a dog's dinner messing around (which is often the case!).