If you have installed SSL feature to your store, the site goes under SSL mode when people click Login, My Account or Checkout. Sometimes this mode could make all of the product thumbnails, buttons and your logo disappear. Even the template seems to change a little bit the color theme.
The admin panel too! You might be busy adding products and all of a sudden pictures and buttons get missing.
Don’t worry. This is because you used hot-link protection while not setting up the https as one of the authorized hot-links in the web server.
The solution is as simple as going into cPanel and adding https to the hotlinks as follows: Learn More