Excellent work! Rated 5 out of 5 stars

You have made this extension really flexible. I can translate the menu and add new search engines really easily. <3

@zenopz: Just do it yourself :) Open the option menu of "Image Search Options" in the add-on manager. Then click "Add" and fill the form like this:

DISPLAY OPTIONS
Google Search

LEFT CLICK SETTINGS
http://google.com/searchbyimage
VARIABLES
image_url=::$URL::

RIGHT CLICK SETTINGS
http://google.com/searchbyimage/upload
VARIABLES ("Use POST instead of GET" checked)
encoded_image=::$IMGDATA::

SHOW ICON (the field on the right)
data:image/png;base64,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