I'm not 100% sure but still as far as I know, saving the image in PNG mode doesn't makes the background white and keep the background as transparent. And you get the rounded image.
The image can't be save according to the border, instead the whole page is saved. So the tricks is to make the background transparent and save the image in PNG, as PNG's can hold the transparent background, and doesn't makes it White like JPG.
This does not help me in my case why ? because suppose the background color of the document is yellow, the logo is round (circular), when pasting the logo onto yellow there is still white rectangle box around the circular logo. As i want only the circular logo without white rectangular border around on say the yellow background.As KS said above, saving the logo in PNG format will get you a transparent background, unless you dint fill anything.