There's no place to type a file name or path in the Open Image dialog!
The browser approach is okay, except for:
1. For many people, typing is faster.
2. If one of the directories on the path to the directory you want to get to has
a lot of entries, you have to search for the entry you want.  This is slow. 
Typing is faster.
3. If one of the directories on the path to the directory you want is on a
network that you want to avoid (because it's down or slow), there's no way to
type past it to avoid the congestion.

In general, please allow for text input when reading or writing files!

Thanks,
Steve