If you want only one tab then if you click on the row customisation icon you should change the 'column presentation' from 'Framework tabs' to 'Framework containers'.

On the other hand if you want to use tabs and have 1 tab but you only want 2 you should (again in the row customisation popup) choose 2 tabs.

Regarding permission to see the other images and folders when using the intro image - this is controlled by Joomla. I'll look into the possibility of being able to add additional constraints on what people can do with the media manager. You may want to look at using an image custom field instead of the standard intro image since this allows you to specify a sub-folder for the images.

Thank you for the answer. I tried the form with permissions for authors to upload an image from frontend (via the editorbutton, only a few buttons). The authors could see only their own images, because every entry had an extra folder. Perhaps that could be a possible solution? But the size of standard image didn`t fit to the easy layout single article, only to the blog article.

Did you realise that in the layouts you can control the output size of the intro image in the field options?

I am working on an image uploader that would allow images to be creator specific (editors could see them all but authors only their own). Watch this space.