First things 1st...
Glad the solution is basically working. Assuming you've not made any changes, other those provided by the original configuration, then, a single click to select any tab, other than 1st tab, followed by <cntl>+D, will duplicate the shape. It will be identical to the originating shape in everyway...color, position, text, font, etc. Merely, right click, and provide new tab position.
Adding pictures should be ok to main shape. Click once to select tab, then shift click to select pix, now use shape operations to add to group.
Adding picture to tab was unexpected...small picture. But, select the main shape again, if it isn't. Then change grouping behavior so it isn't group only. Now click select the actual tab shape. Shift click to select tiny pix and group. That ought to work. Reset main group shape properties to group only.
HTH, Wapperdude