I don't know if there is another/better way to do this,
but having to do it myself - this way works - at least for me
I don't know your situation as far as the sizes etc ,
but if I was going to try it on my site, (using cPanel file manager)
and being one of those "non-web savvy users"
I would just replace the existing image with my new one,
hopefully it's the same size, it makes it even easier...
That way I don't touch the code!
I would first figure out what the image/pic that I want
to replace is called and then I'd re-name it, I usually just
add a 1 in the existing name so that it's there if it doesn't
work - if it works I'll delete it or move it.
Then I would upload the new image/pic and just call it the same thing
as the original image/pic and that should do it.
