I am trying to create a Civ using Charcoal's Add a Civ Tutorial and when I get to Part 4 where I have to resize the flag I try to resize it but only a small portion of the flag appears. Can anyone please help me?

Do you wan't to change the image size or layer size. Because if your enlarging a layer and not the image it woln't all be shown. Make sure your resizing the image. Also I'm not quite sure what you mean so if you could go into more depth I could help you more.

Copy the image to a larger file first, then enlarge it - usually works.

Copy the image to a larger file first, then enlarge it - usually works.

How exactly do I do that?

Select all the image, press Ctrl+c (copy), press Ctrl+n (create a new file), select the size you want (for example, 128x128, the size for a LH), press Ctrl+v (paste) and then enlarge it. Perhaps you need to move the image to make it fit in the screen.
I think, by your description, that the problem is that the redimensioned image is to big to the file, so only a part of it appears at once (if you move the image, another part appears).

Alright I got it now thnx:)