I've always heard these categorized under picture settings. Things like color warmth, black levels, etc., also get grouped here.
Some could refer to these as display settings, too, but generally display settings are more commonly things like resolution. A rule of thumb could be -- if it affects the visual look of the image itself (color, contrast), it's a picture setting. If it's instead more closely related to matching the picture to the display in a technical sense (resolution, aspect ratio), it's a display setting. Therefore changes such as bumping the image up or down a couple of pixels to fit your monitor would be a display setting change.
Generally speaking though the categories are not very concretely defined, and in everyday usage, I don't think anyone would get confused by referring to any such setting by either term.
With dials and buttons on the monitor itself, I usually just group them as "monitor settings," since I also have the ability to alter the image through software. Categorizing it as a monitor setting therefore gives more immediate information than either picture or display would.