It would be nice if when sending an inline image, the custom size would allow me to enter 100% as the width and not supply a height. That way it would perfectly fit the view port of the recipients window. Since we have no way of knowing what kind of device or what the size of the viewport is, 100% width would fix this in almost all cases. Having to select from Large, Medium, Small, or Original are all bad choices. By adding a style element to the IMG tag style="max-width: 100%;" or width=100% would do this nicely.