I don't think you should ever drag a photo from Lightroom to somewhere else.
The proper way is to select the file in Library (in the Film Strip at the bottom of the window). Then press the button "Export". You will then get a dialogue box. Type in the information for the place where you want to save it. Press the button "Export". The changed (edited) photo will then be where you told it to be saved.
(I am a beginner in Lightroom but think the above is correct)
Merci pour votre réponse , ça marche ! Jack Le Roux .