Hi there! I'm not really that good in website building but with regards to your question on placing a picture on your gallery, the things is, you need to upload a picture first in your site manager area, afterwards you get the name of your picture and paste it on the body tag of your site...you also need to have at least a basic knowledge in html.....
If using the free with Wizard you do't have to have any knowledge of HTML. At 86 I am too tired to bother learning it but have successfully put images on 3 sites.