You can press Ctrl+Del to delete all checked pictures.
You can press Ctrl+L to start a slide show.
You can press Ctrl+PageUp to skip to the previous page.
You can press Ctrl+PageDown to skip to the next page.
You can press Ctrl+Home to skip to the first page.
You can press Ctrl+End to skip to the last page.
You can use mouse wheel to change the current picture in full screen mode.
You can use Ctrl+mouse wheel to scroll the picture in full screen mode.
You can use mouse left button down+mouse wheel to scroll the picture in full screen mode.
You can use the Del key to remove a picture.
If you want to re-download removed pictures, select "Project->Database->Optimize project data" from the main menu.