Sizes and dimensions in QML

[Circuits]

I am working on a hand-me-down QML application and I have noticed that specifying a size for one icon in one place results in a different size than specifying that same size somewhere else. So I am wondering, what exactly do these numbers mean by default? For instance:

implicitWidth: 85
implicitHeight: 85

Is the 85 supposed to represent 85 pixels? I am new to QML but it would seem this is alterable, no? The reason I think this is because I set the values mentioned above and then in a different location I set the same values to another button and the two buttons are different size's as measured by my pixel ruler: the latter is 85 and the former is 108 or 109 or so.

[Circuits]

Actually, as it turns out upon further investigation. What seems to be happening is that when I specify the x: and y: location for the image contained within the rectangle (that is of size 85) the size of the rectangle is being manipulated.