Ooh, I used to use picnic - now moved to picmonkey due to the slight closing down soon issue, but the nearest I've found on either is focal b&w which is not bad, but only allows you to select a circle of colour
@rufus430 If you go to iPiccy.com it will let you do color selecting.
You would go to the B&W effect and make your pic B&W. Then select the paint brush icon and make the brush the size you need
You would go to the B&W effect and make your pic B&W. Then select the paint brush icon and make the brush the size you need