I have just read in "The English Blog" of a site which has lots of pictures attached to news topics of the day. It is called "The Big Picture" Click here. What is good about this site is that the pictures are large and easily displayed. Warm-up activities such as "slow reveal of picture" and "guess the picture" would be ideal. Once you have finished the warm-up stage,you could then lead on to a discussion about the topical subject of the picture.