WoWInterface - AceConfig-3.0 Options: How to pass imageCoords?

In AceConfig-3.0 Options you can set an image to be displayed instead of an execute button.

But I don't understand how you are supposed to pass the imageCoords, as it says in the manual:

image (string|function) - path to image texture, if this is a function it can optionally return the width and height of the image as the 2nd and 3rd value, these will be used instead of imageWidth and imageHeight.
- imageCoords (table|methodname|function) - arguments to pass to SetTexCoord, e.g. {0.1,0.9,0.1,0.9}.
- imageWidth (number) - Width of the displayed image
- imageHeight (number) - Height of the displayed image

The 1st return value is the image string, the 2nd and 3rd is are width and height. But what about the imageCoords table??

Lua Code:

image = function()
    -- What do I do with this?
    local myCoords = {0.4, 0.6, 0.4, 0.6}
                                  
    return "Interface\\Transmogrify\\Transmogrify", "20", "20"
  end,

myOptions = {
     type = "group",
     args = {
          myButton = {
               name = "My Button",
               type = "execute",
               desc = "Click me to do stuff!",
               func = function()
                              --do something here
                         end,
               image = "Interface\\Transmogrify\\Transmogrify",
               imageCoords = {0.4, 0.6, 0.4, 0.6},
               imageWidth = 20,
               imageHeight = 20,
          },
     },
}

myOptions = {
     type = "group",
     args = {
          myButton = {
               name = "My Button",
               type = "execute",
               desc = "Click me to do stuff!",
               func = function()
                              --do something here
                         end,
               image = function()
                              return "Interface\\Transmogrify\\Transmogrify", 20, 20
                         end,
               imageCoords = {0.4, 0.6, 0.4, 0.6},
          },
     },
}