Tapping or pinch - to - zooming on a photo expands it to full size and brings up icons in the lower left and upper right of the screen for editing and sharing. (laptopmag.com)
You've probably found it by now but if you tap the screen to get the light / wifi / battery icons in the upper right of the screen and then tap those you will be taken to the settings page with an option to open all settings. (goodereader.com)
When reading a book, magazine, or newspaper, just tap the center of the screen to see menu options — contents, search, brightness, and more — and the bookmarking graphic on the upper right of the screen. (laptopmag.com)