The first picture depicts Meiling (also known as Meilin) "glomping" Syaoran (also known as Li). In this type of a glomp, Meiling is showing her affection in a very enthusiastic and overwhelming manner. It is less of a normal hug and more of an extremely light tackle.
In the second picture, Chibi-Usa (also known as Rini) is glomping Hotaru. She is hugging her friend wholeheartedly, but in this picture, she is not as overprotective and smothering as Meiling is.
Many characters glomp in the way that Meiling is, to show that they care, to get attention and to also show off to others who they feel may be a threat. This is the main use of a glomp in anime.
The second method is that used by Chibi-Usa while glomping Hotaru. A sign of friendship and love with no strings attached. This type is not used to show off or to recieve interest, but just to show caring.
My website takes a look at both types of glomps and the characters who give them. Have fun exploring my website and discovering more about the elusive glomp!