@Zonzon I apologize that I am replying in English, Hoping I can help.
When adding pictures you can click on here.
This will open a box with choices. Make your selection, but then wait for it to upload. You may even see on the right side of your screen your post and picture. I am on my ipad and that is what happens.
Once picture is uploaded completely, you can then Reply (post).
Hope this helps!