Browser extension to add an icon to upload images from a predefined location in a post on Stack Exchange

Question

I'm looking for a browser extension that can:

• add an icon and/or a shortcut to upload an image located in a predefined path in an answer or question on Stack Exchange

For example, I have defined a Dragon NaturallySpeaking voice commands that attach the image C:\Users\Francky\Downloads\Untitled.png when editing an answer (usual filename when taking a screenshot in Windows 7):

Sub Main
    ' http://meta.stackexchange.com/q/2980/178179
    ' opens the "Insert Image" dialog on SO,
    SendKeys "^g"

    ' Attach image in the dialog box
    Wait(1)
    SendKeys "{ENTER}"
    Wait(2)
    originalClipboard = Clipboard
    Clipboard("C:\Users\Francky\Downloads\Untitled.png")
    SendKeys "^v"
    Wait(1)
    SendKeys "{ENTER}"

    ' Click on "Add picture"
    Wait(1)
    SendKeys "{TAB}{TAB}{TAB}{ENTER}"
    Clipboard(originalClipboard)
End Sub

I basically would like to do the same just by clicking or hitting a shortcut. I know I could use AutoHotKey, Sikuli or some other automation software but since StackExchange has many users I am wondering whether there exists some ad hoc browser add-ons.

And if possible:

• works on Windows 7 + Google Chrome
• free