You can find a lot of antonyms in my page, I am sure, Up and down, clean and dirty, big and small, urban and natural... reality and reflection in art... You can pick what you see... just to explain we have a floating statue of two gigantic PET bottles in the lake to make sure people take recycling more seriously...
I too have a couple of antonyms on my page, this is a really fun idea for a challenge My antonyms are: solid/liquid (the title is placed over a beautiful stone walkway around the memorial) the reflecting pool is my liquid. Sitting/standing. The tree is living and the bombed building signifies the deaths that occured.
Here's my take: There are a couple different word pairs that I thought of for this photo: Warm/Cold, Winter/Summer (which is what a Midwest fall really is - a little bit of both!)
Here's my page for the challenge. The antonyms I chose are "Together Apart". The images in the circles are all part of a screen grab of a Zoom call to celebrate a family birthday.