Welcome to the forum!
Perhaps you can give us some more details. Otherwise I would expect that it will be difficult to help you. Or no one will feel motivated to help.
And this is the only help I can offer.
Hello and thanks for the answer.I have some png photos in my desktop.Some days before when i created a new note with the Joplin desktop i could insert them in my Joplin note.From yesterday when i try to do the same either there is error message (just with an x and nothing else) or simply nothing happens and my note is not inserted.I hope i made myself more clear now