Many thanks paulcb. But my problem is not exactly this one. And sorry for the way I use to explain that in English, so it is not so clear.
My problem is the following : now I have already exported on my iPad all the photos I wanted, BUT under the label "Photos Flux"on the iPad, there are a lot of photos I don't want to keep on my iPad. And I don't know the way to cancell them.
Please help me.