Android Custom Backgrounds

I select the custom theme option then select choose image, i choose the image but nothing happens. What might be the reason?

I'm not seeing any issues. Maybe the image is too large?

Ok so i figured it out this bug (probably) by an accident. I can choose one of those stock images but can't upload even though the image's size is small. BUT if I choose a different stock image (except the default one) and then try to upload a custom image, it works. So i have to change default background to one of those stock images then i can upload a custom image. I have no clue why is this happening though

One more thing, when i change the background the way i just explained, if i change the board theme the custom background image only applies on main page (background in games resets itself back to default). So I have to change the board theme first then choose custom background image to prevent this happening.ç

Android