Hi!
First of all, the population cap seems to adapt when you change it. At least in the past, people have played increasing their population cap over time.
Secondly, skill does not impact the fanciness of the images that much. Even Grand Master Engravers still do a lot of the common engravings....
I suggest you turn on revealing engraving history in fortress mode. My guess is that the pigtail is the symbol for your civ or your fortress and thus a common engraving/motif is nothing else is available.
Finally, dwarves take the following sources for their art:
* Things they like or dislike (I have one dwarf who detests toads, but half his images are depictions of toads (^_^;; )
* Fellow citizens with things they dislike/like (those are the "dwarf embraces mules" thingies)
* Local history events (settling of dwarves in your fortress, nomination of nobles in your fortress, death and wounding of named creatures in your fortress)
* Regional history events (historic events like battles/woundings/killings which took place in any of the subregions your fortress belongs to. For instance, my current fortress is located in a jungle dominated by elves and bordering on a human civ and bordering on a goblin civ the elves whiped out - so I get a lot of engravings about elves and humans fighting or elves fighting goblins or elves fighting the demon)
Especially the last point is important in my opinion, so if you want lots of interesting engravings, you need to choose a fortress location at least partially in a contested subregion.
Deathworks