Image.sourceSize applied even if image's actual size is smaller than the sourceSize

Image.sourceSize's documentation states:
"If the image's actual size is larger than the sourceSize, the image is scaled down. If only one dimension of the size is set to greater than 0, the other dimension is set in proportion to preserve the source image's aspect ratio. (The fillMode is independent of this.)"

However setting the sourceSize to a value smaller than the image's actual size, the image is scaled up even though, according to the documentation, nothing should happen.