Fail to upload Icons and Screenshots

In the “Edit Product Page”, I fail to upload Add-on icon and Screenshots.
My files are valid, not so big PNG files. but I have the following errors (even though the preview is displayed correctly): “There was an error uploading your file.” “Images must be either PNG or JPG.”

Any idea ?

Nevermind, I found the reason. The PNG shall not contain “Color Profile” to be valid.