Sorry for the late reply (as always
) and great to hear that you managed to solve it yourself.
I suppose, your item size is actually 96px? Oh, and you can also set the icon size inside the AGS editor itself. Click on 'Maingui' in GUIs (on the right), select the inventory area 'MainInv'. In the properties you can define the correct icon size.

I suppose, your item size is actually 96px? Oh, and you can also set the icon size inside the AGS editor itself. Click on 'Maingui' in GUIs (on the right), select the inventory area 'MainInv'. In the properties you can define the correct icon size.