If I was building a frame that was going to use a 7 sp internally geared hub, I'd use long slot horizontal dropouts. Ceeway in England has some nice ones (N65). I wouldn't use vertical dropouts like the ones in your picture for several reasons. 1st you will have to add a chain tensioner and there is no reason to do that if you are using horizontal dropouts. A 2nd, it is much more difficult (especially for a beginner) to get the chain stays the exact length so the rear wheel centers.
The way you attach your hooded vertical dropouts to chain stays is by mitering the end of the CS to match the radius of the hood and then fillet braze them together with brass (we say brass but really it is bronze). With this kind of dropout, it requires more careful positioning when brazing. Another reason not to use them if you don't have good fixturing.