In which size do u want the concept? just answer and i will start working immediately! Thank you!

Whatever size fits the facebook page. I''m not sure what size specifically. 

Could you provide some more specs about what you need?
- a facebook landing page design
- or a facebook cover image design
- or a facebook post design creative which you plan to promote to get followers

Do you insist on using one of the attached photos, or I can use other graphic/ad photo?
Thank you!

you can use other pics- no problem.
Clearly you know a lot more about Facebook than I do.
I don't know what all of those things are. I'm looking for the graphic people see when they go to my page.

So you mean the cover image (the big vertical image on the top of the page)
Thank you for the answers!