using screenshots as backgrounds

So I got a little snarky... (sorry!) and decided I didn't want to keep loading the million tiles i have in the game for every scene. So.... I create a separate scene with the size i want and place all the tiles on lots of layers. I'll end up with multiple overlapping layers of tiles (trees in front of house wall tiles with a flower under the tree ect). looks real nice.

Then I printscreen (from stencyl) and save the image, create a new scene (this one i'll use), and set the image as the background. Now I just use a tileset of simple blocks BEHIND the background to set where all the collisions are. This worked for the 600x800 level i first drew.

Here's my problem:
My new scene is 80x35 tiles (was shooting large!). I've designed the tiles and printed the screen. it is the same resolution as the original scene (i double checked).
But when i attach it to my new scene as a background it shrinks it (even importing it at 1x!) and there is a letterbox border all around it. The size of the scene in properties is 80x35 tiles, and the size of the image in the Dashboard image properties is the exact same! But the image is always smaller, has a letterbox of space around it, and doesn't even stay where it is if I scroll. 

If someone can help me solve this it'd be great!

Ok... I got it to work one time. I said "attach to scene" from the image manager... why does that work instead of adding it from the scene?
so confused....

Nooo!
as soon as I saved it did it again, it shrank the background to have a letterbox around it. what the heck?

ok. new problem. I managed to get the colisions set to the bg by not saving it after getting everything set up. but now when I test it the background is "bound" to the top right of the screen. it does not scroll with the scene like I thought it would. is this supposed to happen? is this a stencyl issue?

Is it not possible to use backgrounds like this? or is there a way to bind the image to the scene instead of the camera?
I've already noted that the max tile size i can import an image is around 80x30 and not 100x35. Which makes most of my scenes quite small