Do you have a link to the image to see it? I think the problem is that you can’t use an image like that, because you have to take in account that each device has a different aspect ratio, so you can’t use only one image and expect to work across all devices. You have to separate the components in little images for each button, for example.
Fill: The image is stretched to fill the available space. The aspect ratio is not retained.
You probably want to try UniformToFill to keep the aspect ratio of your image. Or, use an image that isn’t set up to fit 1:1 with the screen (because as Juani correctly comments above: there is no way you can expect it to work perfectly on all the different types of screen resolutions and layouts).
If I was putting that screen together, I would separate the image into different pieces:
keep the city-scape as one image, then use UniformToFill on that and place it in the background, and
place those three icons into a Grid and align them evenly spaced and docked to the top (with padding and margins).
That way, you can have those things laid out sensibly on a wide set of devices. Though, to confuse things even more: why do you have those three icons there, as part of your background image? As a user, I would certainly expect to be able to tap them.
Nope, there’s no way that would work. You have to separate the image at least in three parts: 1 for the upper black bar, the other for the Rio background and the third one for the bottom black bar. Then, you can make a Stack Panel with three Panels (or a Grid) and maybe in the Middle Panel use an ImageFill instead of just an Image, something like:
Yes, UniformToFill will stretch your image but keep the aspect. No, there is no way one image can work for all devices out there, and no, you shouldn’t include a bunch of different images to account for it. Split your background up into pieces with code.
Please re-read both mine and Juani’s posts in this thread, as they (as well as the documentation I linked to above) will explain why. You simply can’t use one single image to fit all possible combinations of resolutions and aspect ratios out there – it would be a little like expecting that a single image on a website will look perfectly stretched (without losing its aspect ratio) on all computer screens out there. Can’t be done.