I have a weird behaviour. On a 18.104.22.168 Magento installation, I try to upload product images: if no image with that name is already existing, everything works just fine, otherwise it tells me that everything is fine but when I go with the mouse over the new image I see js error that the image (_1 appended) does not exists, and in fact actually it's not there.
Thanks a lot
This is how Magento 1.9.x works - it requires unique image names. If the image name you are trying to upload already exists, it will rename it with _number