Is there a way to resize my Photoshop document without effecting layers?

Question

I am making a website mock-up with photoshop and currently my image size is 1020x807. I am wanting to add a great deal more of height to the "canvas" so I can give example to a largely scrolling page. Maybe something like 1020x5000?

However, if I change the height of the image or canvas it will change all of my layers as well. What is the best way to do this without having to make a new document and spending all the time transferring my layers over?

To put it even more simply...Is there a way to enlarge the size of my document without effecting the layers?

Thanks in advance

Answer 1

Image > Canvas Size...

Simply enter the size you want, set the way you want the canvas to expand, and click OK.

Note: Canvas Size is not the same as Image Size. Canvas size changes your canvas without altering the size of anything else.

Answer 2

I'm not sure how to reduce the image size without resizing the layers, but just in case someone else isn't able to provide you with a more direct solution:

Couldn't you make a new document at the appropriate size, put all your layers + groups into one parent group in OldDocument, and then just transfer the parent-group over to NewDocument? Drag-and-drop the cursor in the center of your new document, and your layers will be centered relative to the new navigation-area size.