As I said way back in the beginning of all this.. I 'guessed' that the final icon size is 48x48..
http://i48.photobucket.com/albums/f2...rlay_Size1.jpg
If you look at this image, the Underlay I made is a 48x48 gradient filled box with a 1 pixel border and the outer corner pixel of the 48x48 box is colored to match the border. This gives a quick 'rounded' corner look to the box.
Beside it is an actual inventory underlay icon from AO. it is 54x54 in size. I took a 48x48 size box and stamped it centered on the AO icon. the 48x48 icon seemed a perfect fit. So, I guessed that the actual icon sizes used in AO are 48x48.
I also noticed that all the icon images at Auno.org or the aodb site are 48x48 .gif images. Scanning screen shots of the game with many backpacks open (zooming in) seemed to support that the icons in AO are using a 256 color 8-bit palette.
That is how I arrived at the 'Guess' of the final icon size being 48x48 in AO.
That said, I am still waiting for replies to my Inquiries about the 'official' icon size and file format. (I sure hope they can use .png images in the new engine with proper alpha channel transparencies) I can make my icons 256 color .gif with a transparency, I got the tools to do it. But my fingers are crossed for .png support in the new engine.
There it is in a nutshell, everything I know about the AO icons.
Cheers!
P.S. I added a 4th icon that I made based on the current AO Underlay, using the AO colors but upgrading the gradient fill and icon to 24 bit color.