Hi Sally64, welcome to the board. With my moderator hat on, I have reset your images as attachments to the post rather than inline URLs to the "postimage" site. This is the preferred way of adding images as it retains them in the post without the possible loss that so often happens from a 3rd party site. And, as you will see, the board automatically creates a thumbnail for initial viewing and single click then displays it full size.
To make the change I made a temporary copy of your images and used those to insert as attachments. No editing was done to any of the images and I have now deleted the temporary copies.