Hi Rohit, It is very strange, isn't it. I can't work out what is causing the problem.

My current code is:

Export["pic.png", 
 Graphics[{EdgeForm[{Thick, Green}], Frame -> None, 
   ImagePadding -> None, PlotRangePadding -> None, 
   Rectangle[{0, 0}, {640, 480}], 
   Style[Text["some text", {120, 50}], FontSize -> 24, 
    FontColor -> White]}]]

And that produces:

Although it isn't clear, because the background of this forum is also white, there is definitely a 5px'ish border. When I import the image I can see it more clearly. I will try cropping it within MMA, and exporting the cropped image to try and work out if the problem is with Graphics[] or Export[] - which seems unlikely.

Cheers Andy

Hi Gianluca, Thanks very much for your thought. I have revised my code, but the image still has a white background. I wonder if there is a way to trim the image after I generate it. Perhaps that's a better approach.

Export["pic.png", 
 Graphics[{ Frame -> None, 
   ImagePadding -> None, Rectangle[{0, 0}, {640, 480}], 
   Style[Text["some text", {120, 50}], FontSize -> 24, 
    FontColor -> White]}]]

Cheers Andy

Maybe you can try the option PlotRangePadding -> None.