From what I see tread is good. How old is the tire and how do they ride. Rubber becomes hard with age and lose grip. Tires over 5 years old are nearing the end of usefulness. Here is how read date code.
The rear tire looks great, cant believe it has 12,000 miles on the tires. It looks like your front tire is the original tire and the back has been replaced once - usually the front tire will last for two rear tires.
The front tire has wear bars molded into the thread. When its worn down you will see horizontal bars across the tread gaps. (not there yet).
There is very little difference in wear between the rear tire and the front tire. The front one is dusty and that takes away relief in the image. I keep my bike at my daughter's place and there is about a mile of gravel road to get to her house.
It may just be the way the light is hitting it, but the front looks like its due for a change. Tread is ok, but wear pattern isn't. As soon as you ride it with a new tire on it will make sense. Back looks fine.
To be sure of where you are on amount of tread, use a tire gauge and measure tread depth when new, then write down the depth periodically (I do that about every 6 months or with some other work on the bike). Down near 2/32" is time they need to go. Although most owners will change out before a trip if they think they'll need tires while on the road as you can never be sure if what you want will be available.