But I still have the problem.
I have upload the album 4-5 times.
Then I have two times delete the album and created a new project.
Then I have created a project only with picture (.jpg, without videos(.mp4))
I can change online the titel-picture of the album and see the selection of alle the picture.
That's why I'm sure, that all picture are uploaded.
I try the Tiger-Skin and the Base-Skin.
I try a own folder for the album of my HDD and the default folder (My Albums)
I try it on Firefox (actual), MS-Edge (actual), Tablet (Android 6.0.1) with two different browser. Always the same result.