Unfortunately no :-( There is two settings to control the image size reduction operation: One affects the dimensions of the image, the other affect jpeg compression. It's possible to keep the original dimensions {x, y} and apply a minimum compression ratio, but there is no way to just turn off this feature completely.
From a user point of view (regarding usability ergonomics), imho i think it's important to allow clearly an on/off setting on this, it's clearer than keeping the feature turned on, but with no effects due to parametrization.