Save Image As And Close Tab Firefox Addon

I haven't made a firefox addon before, but I thought I'd try something simple: combine the context menu "Save Image As..." with closing the current tab. My contribution consists of putting these two lines together:

gContextMenu.saveImage();
gBrowser.removeCurrentTab();


To start out with I used the Firefox/Thunderbird Extension Wizard. Initially I didn't select the 'Create context menu item' and that may have caused problems with gContextMenu not being defined - it was either that or the fact I was trying to embed the commands into the firefoxOverlay.xul file as embedded javascript instead of putting it in the overlay.js file.

I found the first function by looking through the firefox source code first for the menuitem name of the function "Save Image As", and from there finding saveImage. The removeCurrentTab function was harder to find, but this addon provided source code that showed it: Stephen Clavering's CTC.

Tutorial pages I initially found about extension development were helpful, but I didn't see anything that talks about mozilla fundamentals- probably I need to find a book about it.

This addon goes well with the Menu Editor and Download Sort.

There is code in the real Save Image As for determining whether an image is being selected or not (my addon shows up regardless) I should add in next, and there should be logic that prevents the close action if the save as was canceled (less sure how to do that).