I preferred the flags that were submitted in the perspective challenge to this kind of straight ahead view. It's very flat. I like a photo to have depth (just a personal bias).
I love our flag too, but IMO there needs to be more in your picture. It just sticks out from the pole and has little interest. Maybe if you had positioned yourself to get some depth or perspective in the shot it would have made it stronger. 4
Flags are so common that they really need to be outstanding to attract a photo buyer. While it's a good photo, there isn't anything which really grabs my attention and makes me think that this is a "MUST HAVE" photo. Mostly in focus and the exposure is good.
Nice composition and, I usually don't pay attention to the framing but it really works on this. I like the the red, white, and blue flag against the blue background with red and white borders. Nice detail on the flag.