SAMPLE 1
A pair of 4x6 landscapes separated by a white divider line.

Normally, I do this by adding a white border to the right of the first image (first image width + size of divider line). Then I import the second image and, through painfully cumbersome scrolling and zooming in, I move that image into the right corner to even with the first image, leaving the white divider.
What is a more efficient way of doing this?
SAMPLE 2
Two fruits set vertically in a horizontal (rough) alignment.

Normally, I do this by importing the first image and either increasing the canvas size or adding a border vertically. This pushes the first image up/down to the edge, anticipating space for the second image in the center. I import the second image as a new Layer, which automagically puts the image into the center. Sure, this is an exact horizontal center, but I still have to finish vertically centering.
This scenario should also apply to a horizontal side-by-side image alignment, just as well as a vertical text-with-image alignment (i.e. a "For Sale", "Missing" or "Wanted" sign.)
What is a more efficient way of doing this?
If anyone might be able pass along a few pointers/suggestions or tips/tricks I may not be aware of, this is much appreciated. Thanks!
