I'm not a computer expert, so someone feel free to correct me if I'm wrong!
To embed a photo, you first have to either upload the photo here to the gallery, or else use a free online service like Photobucket to store your photos. Then you copy the url or address of your photo and paste it in your posts, wherever you want the photo to go. Let's say I want a photo of my doggies here. The address of my photo at the photobucket web site is:
So I click on the yellow picture with the little mountain right above the text box where I type, and up pops a little window asking for the url location of the photo. Fill in the url of the image, click ok, and here's the photo:
When you embed an image from the gallery, make sure that you select the text that is in the box. As shown in the screenshot below. You can then copy and paste that text into the posts you want to show the picture. :)
The box containing [URL] only gives a link to your image.