AutoFit, AutoStretch and AutoShrink all must be false, then use Stretch:
TImageEnView.Stretch
Declaration procedure Stretch;
Description This method sets ZoomX and ZoomY values to stretch the image to fit within the component borders.
Note: Using this method you will lose the image aspect ratio and some functions, which require aspect ratio, may not work properly.
ImageEnView.Stretch;
If ImageEnView is client aligned and the dimensions of ImageEnView changes like when maximizing the form or when resizing the form you have to call Stretch to stretch the image to fit the new component dimensions.