Don't worry about it, Emma!

There isn't a hard and fast rule about sizes, but if something is huge I'll be resizing for the sake of convenience...and as you say, you can provide a big scan to anyone who wants one, via email.
Incidentally, the original image you posted (the huge one

) was quite badly pixellated because it was at a low resolution, so to make it clearer it had to be shrunk anyway. It's a juggling act to get images the right resolution, the right physical size, and the right file size to fit on Rootschat!

Takes a bit of practise, but it's worth the effort

Cheers
Prue