Forcing sort on find because the file order of find output is inconsistent across different Unix systems. Also switching to a five-digit leading zero for temporary tile names because with 8x8 pixel tiles, reaching more than 10.000 tiles is not unlikely. Finally, forcing our counter for hand-over to jpegoptim to use Base10 instead of Base8 despite the leading zeros which Bash was assuming meant Base8 due to its proximity to C