So, so many design mistakes in that room. I won't even go into style choices, but I'll just mention the basics.
1) The top of the curtains should be the same height. Bring the one on the right up to match the one on the left. That'll cover your brackets on the right.
2) The bottom of all of the curtains in a room should be the same level. Even though windows/doors are different sizes, the curtains should be the same. That means you need new curtains and gives you a chance to fix the bracket issue. Or, if you are going to ignore the equal length curtain rule, then just move the one on the left up and it'll fix the bracket issue on the left.
3) The bottom of the curtains on the right should not be so long that they are breaking on the floor. Again, move the curtains on the right up.
But I agree with Leros, if you don't want to do much, just paint the brackets. You'll hardly see the bracket issue any more. Another simple fix would be to carve out the drywall/plaster behind the brackets and imbed the brackets slightly into the wall. Cover with mud, paint, and they are invisible.