Adding icons and widgets

How do I add icons and widgets ?
Incorporating icons as images is that the only way? or can we add icons like arrows and stuff in the same way we include symbols?

Yes, you can only create icons as images.

Is there a way where the content(like labels,icons and stuff) of the screen will stay similar or adjust according to the screen resolution? When the resolution of the screen is increased or decreased?

This is currently not possible, but we will support this feature in the future.

so, now in this image I have to change the value from off to on and viceversa when I press the value or something. How can that be done?

You can change property of the label with event or have 2 labels on top of each other and show/hide them with event based on some value.