Yeeeeessssss It worked this time! Thanks, Andrew, for the FILE.TIF.#### !!!
I couldn't find a way to render it in this format, so I discovered an amazing free software ( http://www.bulkrenameutility.co.uk/Main_Intro.php ) that allows us to do whatever we want with the name of our files... and then apply it to a looooot of files at the same time. So I renamed all the tiffs (jpgs in this case... it was tooooo heavy!) andMR could finally read it. XD isn't it cool?? So I have the tree textured in 15loopable secs. It can seem too much... but I wanted to be prepared even for the longest scenes. And the render was taking me forever, so I put the settings down to make it possible in some hours. I really loved the look of this tree! Now I just need to decide what to do with the leaves ;)