How can I delete the pictures on my yahoo mail account?

If these are in My Photos and My Attachments then you must delete the email they are in. Inbox, Sent and Trash. Click My Photos and then at the top of the pictures click Message View. That will bring up the email they are in. To delete separetely, click the little box before it and delete. It you want to delete the entire page scroll to the bottom and click Check all then delete. But it is best to go and find the email and delete from there.