Difference between SD and HD Pictures
Sd pictures are somewhat blur as compare to High definition pictures. In HD pictures you can clearly see the wrinkles, shape of hair and each fair features of face however, in SD you can't notice see fair descriptions.
The difference is quite obvious due to difference in pixels. SD pictures has 480 pixels, however it's rival has 1080 pixels. Pixel is the point of screen. Due to compactness of pixels and it shows remarkable details of pictures. You can check the quality of SD and HD videos while playing videos on internet.
Here are some pictures to show the difference between them.