Alpha Channel...

[rich2005]

Quote:.....i get like the first photo you,ve shown with the patterned but the picture itself has the normal border around it....

Again not sure what you mean by normal border however, this using the default dark theme (which I do not normally use)

   

The yellow dotted line is the 'edge of layer' marker, one layer so also the edge of the image. That is the size that you get when you Save or Export the image. The Image size in pixels is also shown top of the Gimp Window.