Finding image links...

How would you check a html document and find all the image links? this has really confused me as i cant work out how to do it because all the image links are different lengths, so i need it to check the first 4 characters and see if they equal "<img" i can do this but then i need it to add all the other characters to the link untill it gets to the next ">" character and this confused me...

writing that has just given me an idea. hehe but please post an answer as my idea is probably wrong.