Deleted image still online

Hello,

When I add a picture to my photo library, and that I go to mywebsite/wp-content/uploads/2016/04/myphoto.png , of course, I see the picture.

When I delete this picture from my photo library and that I go to mywebsite/wp-content/uploads/2016/04/myphoto.png, the picture isn’t there anymore. Everything is normal.

Except for that one picture that won’t disappear ! It’s a 2Mo GIF, that I would like to delete, that doesn’t appear anymore in my back office, but when I go to mywebsite/wp-content/uploads/2016/04/mygif.gif , it’s still here. I’ve change navigator, computer… the link still works.

And it’s for that only gif. I tried to delete other gifs, and they get deleted like any other picture… How can I get rid of that particular one ?

Thanks 🙂