Looking for a little help with Pictures?

Question

1)Is it possible to change the percentage of a picture and save those changes?
I am trying to make a CD for family members and I would like it to open at the right size when they double click on the thumbnails instead of having to zoom in or out or increase the percentage.
Is it possible? If yes, can anyone please walk me through it.
2) If my pictures are saved in JPG can any computer open them?
Thank you all for helping.

Answer 1

If you want to keep the same quality of picture, I would change the resolution.

This is done a lot for commercial printers. The side-effect of this is the screen apprearance is made larger or smaller. But you don't lose any "data".

In fact, the person at the other end can reverse the process with no loss.