I don't have any advice on making smilies, but there is a feature of GIMP that is rarely discussed which might be helpful. That feature is the ability to show simultaneous multiple views of the same image with, for example, one view being at actual size, another being zoomed in a bit, and yet another zoomed right in to the pixel level. You can edit your image in any of the views you wish and the changes will appear in all of them (painting will only appear in the active view during the brush stroke, but the other views will get updated once you release the mouse button).
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When you create your new views, I'd recommend using the tearoff menu feature. Tearoff menus are available by clicking on the little triangle in the upper-left corner of the image window. The menu that appears is just like the one in the menu bar across the top, except that each of the submenus has a dotted line across the very top. Clicking on this dotted line will create a new window containing just that submenu. By tearing off the View Menu, you can quickly add your new views and adjust the settings to each of them as you prefer (for example, for the "actual size" view in the above screenshot, I disabled the menu bar, the rulers, the status line, the scroll bars, and the layer boundary). After you've set your view preferences, you can close the tearoff menu by clicking on the dotted line. NOTE: you can also access tearoff menus by right-clicking in the image window.
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SStearoffmenu.png [ 28.6 KiB | Viewed 2392 times ]