To give the card a custom size, drag the handle at the bottom-right of the card miniature.

This will be the card height in pixels.

This will be the card width in pixels.

To choose a popular card size, use the pop-up menu to the right.

The stack will open in a new window. To show the stack in the active window (and to close the current stack), uncheck this box.

To create the stack in a new window, leaving the active stack open, check this box.

The new stack will have the same background as the current card. To create a blank background instead, uncheck this box.

To give the new stack the same background as the current card, check this box.