Set up a table with one record for each movie. Define a container field in that table. Insert the Cover image file into the container. Set up a list view layout based on this table with the container field included in order to display the inserted covers.
so far okay for a view in a column. But I want to see it also in a row. E.g. 5 cover in a row and as many columns as needed.
If you want something different, you need to say that in your original post as my crystal ball is not reliable.
"As many columns as needed" is not an option for a FileMaker layout. If you want a grid arrangement, this is possible, but it will have a fixed and predetermined number of columns.
You could set up a repeating field or multiple container fields per record to get your multiple columns, but the better approach is to set up two tables with a relationship linking the two and then set up a series of one row portals to the table of cover art in order to get your grid of covers. You can use Form View and set up a Grid all on one record of the layout's table or you can use List View and set up one row of your grid with multiple records in your layout's table.
You can set up a relationship with the X operator to link to all records in the cover art table or you can set up a relationship with categories, genre or something if you want to link selectively to your cover art records.