Hello @tuhamworld
you doing great well done
the white background is part of the image it self for the first 3 image but the svg is a vector graphics which you can think of it draw the image based on mathematical way and it represented in xml so you can open the file and edit it as if it was text file so the svg is just that shape the you see that why you see the real background which is some kind of pink
ofcourse other image could be transparent but the person who create it should do it based on his/her tool like photoshop or something
check this https://developer.mozilla.org/en-US/docs/Web/SVG for extra info about the svg
hope that help and have a nice day