Internal function that determines when to resize by width or height in a Image Resizer utility
You can replace this:

if (computeWidth)
    return sourceDimension.ResizeWidth(maxWidth);

else if (computeHeight)
    return sourceDimension.ResizeHeight(maxHeight);

else return sourceDimension;


with this:

if (computeWidth)
    return sourceDimension.ResizeWidth(maxWidth);
if (computeHeight)
    return sourceDimension.ResizeHeight(maxHeight);
return sourceDimension;


I would rename the method and input parameters, as it would add more sense to the method name and input parameters.

private Dimention2D  ReSize(Image image, int requireWidth, int requireHeight);