How can I "attach" a picture from "Pictures" to my Yahoo Emails?

I have new Toshiba laptop and love it. I'm no computer expert and sometimes I have problems determining what I should do as in this case: My granddaughter created a folder of her prom pictures in "Pictures". I would like to email these pictures to others and I tried a few things but nothing worked. I know there's an easy way and you might know. So my question is how do I email a picture from "Picture" to others??? Thank you!