Screen Capture Elite lets you save or copy complete, visible or regions of any webpage as either a jpeg or png image file. To use Screen Capture Elite all you need to do is left click the camera icon in the status bar once for the default action. To see what your default action is set to, you need to go into Screen Capture Elite options. To change to use an action different from the default then you can right click the icon instead. From there, you can then choose the action you want to use: save, save as, copy > complete page, visible page, region.
Screen Capture Elite is also customizable. In option you can change the background colour, selection colour, border colour, thickness, opacity and scroll speed.
Screen Capture Elite is very lightweight and easy to use and full instructions are on the website and come with the addon.