The holidays are over and I had to dig through heaps of vacation pictures and wanted to create a little photo gallery for my fellow relatives to click through. After past experiments with Zenphoto and Piwigo, I wanted to switch to a much more simpler solution. One that wouldn't require a database backend and maybe didn't break after a few update cycles.

Looking at static image gallery generators I decided to try llgal again. The command line switches are more difficult to remember than tar, but here we go:

llgal --www --sort revtime --ct %Y-%m-%d -a -d . -k --title "Pictures of Foo"

This will process pictures in the current directory, with the following options:

--www           make all llgal files world-readable
--sort revtime  sort pictures in reverse-mtime (oldest pictures on top)
--ct %Y-%m-%d   use image timestamps as captions, YYYY-mm-dd
-a              write image sizes under thumbnails on index page
-d              operate in directory <dir>
-k              use the image captions for the HTML slide titles
--title         title of the index of the gallery

So far, so good. But some obstacles had to be tackled first:

Each picture on the camera was ~3-5 MB each and I didn't want to upload these large files to the gallery. So I resized the pictures with some photo program (not with GraphicsMagick) but now the file's mtime got mangled. GNU/touch was able to fix this.
The pictures were taken with two cameras. Unfortunately, one of the cameras had its system time off by two hours - this had to be fixed as well.

As all the pictures (from both cameras) are now in one directory, this is how it looked like:

$ exiftool -s DSCN_001.jpg IMG_002.jpg | grep ^DateTimeOriginal
DateTimeOriginal                : 2015:12:23 18:01:00
DateTimeOriginal                : 2015:12:23 16:03:00

In reality, DSCN_001.jpg was taken at 16:01 and should be listed before IMG_002.jpg. Luckily exiftool is able to correct the EXIF data:

export delta="00:00:00 02:00:00"            # format is YY:mm:dd HH:MM:SS
ls DSCN* | while read f; do
  echo "FILE: $f"
  exiftool -P -ModifyDate-="$delta" -DateTimeOriginal-="$delta" -CreateDate-="$delta" "$f"
  touch -r "$f" -d '-2 hours' "$f"
done

Although we corrected the file's mtime already, it was still mangled by the previous export step. Let's just extract the exact date from the EXIF data and correct the mtime again:

ls *JPG | while read f; do
  echo "FILE: $f"
  TZ=PST8PDT touch -d "$(exiftool -d %Y-%m-%d\ %H:%M:%S -s "$f" | awk '/^DateTimeOriginal/ {print $3,$4}')" "$f"
done

After another llgal run, the pictures were now listed in their correct order and ready to be consumed :-)