modify art page to display thumbnails

thumbnails are currently created using shell script and require
imagemagick installed on the server. i know it's stupid, but i think
that including thumbnails to repo is also stupid.

maybe later i replace this script with actual jekyll plugin, but for
this i'll need to familiarize myself with ruby.
but now i use following addition to the git hook on the server:

```
[ -f "$TMP_GIT_CLONE/art/thumbs.sh" ] && {
    dir="$PWD"
    cd "$TMP_GIT_CLONE/art/" && sh thumbs.sh && cd "$dir"
}
```

it happens after cloning to remote repo and before building with bundle.

overall, this is a bodge now, it recompiles all thumbnails every time
due to quirks in my current setup.

2 files changed, 56 insertions, 0 deletions

diff --git a/art/photos/pyramid.jpg b/art/photos/pyramid.jpg
index d439f6f..5524a91 100644
--- a/art/photos/pyramid.jpg
+++ b/art/photos/pyramid.jpg
diff --git a/art/thumbs.sh b/art/thumbs.sh
new file mode 100755
index 0000000..758b0a9
--- /dev/null
+++ b/art/thumbs.sh
@@ -0,0 +1,56 @@
+#!/bin/sh -ex
+
+_img_dirs="$( find . -maxdepth 1 -type d | sed -e '1d' -e 's/^\.\///' )"
+_thumb_size="835x"
+_thumbs_dir="thumbs"
+_force_render=0
+
+usage() {
+    echo "usage: $0 [-f|--force]"
+}
+
+[ -n "$1" ] && \
+    case $1 in
+        -f|--force)
+            _force_render=1
+            ;;
+        -h|--help)
+            usage
+            exit 0
+            ;;
+        *)
+            usage
+            exit 1
+            ;;
+    esac
+
+for dir in $_img_dirs
+do
+    cd "./$dir" || exit 1
+
+    [ -d "$_thumbs_dir" ] || mkdir "$_thumbs_dir"
+
+    _imgs="$(find . -maxdepth 1 -type f | cut -b 3-)"
+    for _img in $_imgs
+    do
+        _ext="${_img##*.}"
+        _name="${_img%%.*}"
+        _thumb="./$_thumbs_dir/${_name}_thumb.${_ext}"
+
+        [ "$_force_render" -eq 1 ] || [ ! -f "$_thumb" ] && \
+        {
+            # when compressed, gifs look ugly, so just copy them
+            # i know this is bad, but i'll adress it later
+            [ "$_ext" = "gif" ] && \
+                echo "copied $1 to $_thumb" && \
+                cp "$_img" "$_thumb" && continue
+
+            echo "creating thumbnail for $_name..."
+            convert "$_img" -resize "$_thumb_size" "$_thumb"
+        }
+    done
+
+    cd ".."
+
+done
+