Tobye On Kongregate you can use a min and a max size, it worked for another of my games, that game used Scale Outer, but when viewed in a smaller resolution the graphics would be smaller, and reveal more or less of the world depending on the aspect ratio, of course, for that you need to prepare your layout for using that.
Before testing the game, I was fearing that the sprites wold be tiny, because the original resolution of the pixel art character was 16x16, but it worked flawlessly on Newgrounds, Kongregate and on mobile.
That case was different, because Construct was scaling up the graphics. I never test it in my own site, so I don't know about that, sorry.