what is a context menu:

A context menu is a right-click menu. It is called a context menu because the menu changes based on what you click on. You use it rather intuitively but if you look at the following page you will get a much better idea of where they are and of how they change based on what you click on.

Right-Click Menus and Toolbars in Firefox

http://dmcritchie.mvps.org/firefox/rightff.htm

also take a look at the supplementary page in pictures, which also shows how you can rearrange menu items in menus including the context menu with the "Menu Editor" extension.

Firefox Right-click on Link Comparison

http://dmcritchie.mvps.org/firefox/rightff_compare.htm

Please mark "Solved" one answer that will best help others with a similar problem -- hope this was it.

It looks that you need to right click an image (any image will do) on a web page to tun that image into a puzzle.

With Puzzle you can turn any image opened with Firefox (on the web or stored locally) to puzzle pieces and play. You can start playing on a low level (4 elements) and advance to higher levels - make it more difficult - upon completion. Have fun!