In Path of Evil, I used GIMP to add a painted effect to area screenshots. For Crimmor, I wanted a more personal feeling. I elected to use unedited screenshots, generally from viewing angles the character would have. I added area name to them since the character is a local to the city and would know the name of the area, assuming there is a unique name.
For the text, in GIMP, add a text box. The font I picked is called killigraphy, a freely downloadable font. You can get it from http://www.dafont.com/killigraphy.font among other places. You can see from the font map the letters have a sharp look, reminding me of a rogues' typical weaponry. A number of letters have a particularly "weaponlike" look, particularly f, j, and t. It doesn't have capital letters. I used 72 point, centered. To give the written text a more 3d effect of still liquid ink (fluid, smooth, changeable, like a good rogue), after typing in your text, select Filter -> Decor -> Bevel from the GIMP menu. I used default bevel settings.
For the curious, the Auric Commorancy is a the name of the city's temple to Waukeen. I used a thesaurus to come up with some interesting sounding words, auric means pertaining to gold (Bond fans might remember the villain Auric Goldfinger), and commorancy is a dwelling or residence. So it's just a fancy name for "Gold House", fitting for a temple to Waukeen. Most named buildings have their named taken from the Dragon magazine article on Crimmor, written by Ed Greenwood (creator of the Forgotten Realms setting) himself.