Janet -

Here are:

-  two versions of Alaska, Light and Dark
-  three versions of Mountain Lake, the original, Edit #1 on which I softened the edges of the more distant objects, and Edit #2, in which I was
   very naughty, softening even more edges and (gulp!) also shifting the copse at the center to be a bit off-center (plus a few other little touches - do, pray, forgive me);
and
-  two versions of Pansies, Light and Dark

I've sized each to be within the specified dimensions, which are max 1200 x 800 pixels.

The mats' colors can be altered as you desire.

Regard these as starting points.  I can make whatever further adjustments you'd like in brightness, contrast and intensity.