Image manager cache bug in 1.9.4.1 "Faanui"

[zspectrum]

Thanks for the update of the 1.9.4.1

But there is still a problem with the cache of the image manager : when you delete a picture then upload one with the same name, it is the thumb of the old one which appear in the image manager.
But when we use the wysiwyg it is the right image, the problem appear only for the thumb view.
The bug does not appear all the time, it is strange and I guess will be more difficult for correct it.

Quentin