Resizing an Image

As an example, say I have a white background and a small square exactly in the top left corner. When I enlarge the black square by transforming it and pulling out on the lower right corner (of the square) in towards the center of the screen, the top left corner of the square doesn't stay in place. Instead, the top left corner of the square becomes larger and moves outside of my entire white background. Is there a way to make the top left corner stay in place and just enlarge the other corners of the square proportionally?

click and hold [strike]CTRL[/strike] OPT/ALT while dragging the handle …

Wow, Thanks! It was the alt/option key on my MacBook PRo that worked for me.

yep, here too

(always mixing ctrl and alt (here) and opt (there)