The thumbnails below are linked to 4 galleries. The first one will open a 1200px tall image in normal mode. Depending on your wndow size, you will most likely need to scroll to see the entire image in its natural size. The second thumbnail launches the same image in Fit Mode. Fit mode will ensure that your image is proportionally scaled to be no higher than your browser/device window.
Use Fit mode for large images when you want to make sure they never exceed window height. Fit mode is for image slides only and can be set for each image slide independently.