when i link a image in my page, the background becomes thick navy colour and takes little space from up, bottom, left and right sides. I can change background colur but i cant remove those spaces that come out when i made image a link.
Those are the edges of the button the image is placed on. They are like the edges of the buttons at the ends of the scrollbar. Watch what happens when you press one.
The navy color indicates the button is selected. Selecting something else moves the selection there. Note that the first link on the page (in html code order) is always selected when a page loads. This tells you what link will be followed if you press ENTER.