I'm looking for a browser extension working on any cross-platform browser such as Firefox, Chrome or Opera.
This extension should let the user drag a rectangle on an image, and give him the position and dimension of this rectangle. The position should be relative to the top left corner of the image.
I've found a Firefox extension MeasureIt that allows to drag a rectangle and obtain the dimension but not the position.
There is also the JQuery plugin imgAreaSelect that allows to retrieve position and dimension but it's not bundled as a browser extension.