I tried to make a picture my background photo i mad sure it was a .png file but it came up as a white background

You have to copy the link

try using another image, for some reason it doesn't show right

1. Click "Pick"
2. Click "Choose File"
3. Pick your background image
4. Click "Upload"
5. Copy the link
6. Paste on "Customize Theme" = "Background Image"
7. Click "Save changes"
8. Done :)