For the image to show, it must end in .jpg. The way I do it is to right click on the image from your hosting site and select "open image in a new window". Then, copy the address in the new window, making sure that it ends in .jpg, and use the "insert image" tag and paste in the window. It sounds harder than it is.
Nice reports, by the way. The Sierra Gorda is one of my favorite places in Mexico.