Ok, I found the problem. I had to swich from legacy to stable environment in my OVH admin section, then imagick is now enable. Hope this will help someone else 🙂
I’ve installed a WP on local and it works. Then I’ve installed a WP on a test folder and the problem happens again. So I guess this is a server problem. PRobably the GD or imagemagick library.
GD is enable (version bundled (2.1.0 compatible)) but I can’t find imagemagick in the phpinfo. I’m hosted by OVH and have no idea how to proceed to activate it. I will make some further searches on Google…
to 150 (in /bp-core/bp-core-avatars.php line 35), instead of 450 originally, then I’m able to upload images from 151 of width. This must be the max-with but it behaves like a min-with. I continue my investigations…