Hi Benoit,
If you are facing this issue due to W3 total cache then try to select manual mode under minify option instead of auto.
Incase if you want to minify css and js then put the path manually. You will get all these under minify option.
Try to select Manual mode under minify option instead of auto.
Once I deactivate the w3 total cache then I can upload images to media. However if w3 total cache is activated then uploading features doesn’t work.
