AppleScript which uploads images easy using Transmit on OS X.

FTP Upload.applescript

set dateDay to day of (current date)
set dateMonth to month of (current date)
set dateYear to year of (current date)
set dateTime to time of (current date)
set nameMonth to month of (current date) as string

set currentDate to dateDay & "-" & dateMonth & "-" & dateYear & "-" & dateTime as string

tell application "Finder"
	set thisPicture to selection as alias
	set the name of thisPicture to "screenshot_mac" & "_" & currentDate & ".png"
	set name_chosenPicture to (get the name of thisPicture)
	set chosenPicture to (POSIX path of thisPicture) as text
end tell

tell application "Transmit"
	activate
	set myFave to item 1 of (favorites whose name is "YOUR TRANSMIT FAVORITE")
	tell current tab of (make new document at end)
		connect to myFave
		tell remote browser
			set lastPicture to (get the name of the last browser item whose name starts with "screenshot_mac")
			if (lastPicture is not name_chosenPicture) then
				upload item at path chosenPicture
			else if (lastPicture is name_chosenPicture) then
				delay 1
			end if
			set pictureURL to (get the path of the last browser item whose name contains nameMonth)
		end tell
	end tell
	close front window
	quit application
end tell

set the clipboard to "YOUR BASE URL" & pictureURL

Awesome! This is the closest I have found to what I'm looking for.

Do you know if you can save a favorite? I've been trying for hours without any luck. I think there are no methods / classes to do it.