Add more qpdf options for smaller file sizes

optipdf

@@ -2,6 +2,7 @@
 # vi: et sts=4 sw=4 ts=4
 
 PRESERVE_TIMESTAMP=0
+LOSSY=0
 KEEP_BACKUP_SUFFIX=.old-unoptimized
 
 TEMP_FILES=()
@@ -126,6 +127,20 @@ use_smaller() {
 TEMP=$(mktemp -t "${0##*/}.XXXXXX")
 TEMP_FILES+=("$TEMP")
 
+QPDF_ARGS=(
+    --compression-level=9
+    --deterministic-id
+    --object-streams=generate
+    --recompress-flate
+    --stream-data=compress
+)
+
+if [[ $LOSSY -ne 0 ]]; then
+    QPDF_ARGS+=(
+        --optimize-images
+    )
+fi
+
 ERRORS=0
 FREED_TOTAL=0
 for FILE; do
@@ -133,9 +148,7 @@ for FILE; do
     BEGIN_FILESIZE=$(file_size "$FILE")
 
     if
-        qpdf \
-            --recompress-flate \
-            --stream-data=compress \
+        qpdf "${QPDF_ARGS[@]}" \
             -- \
             "$FILE" "$TEMP" &&
         use_smaller "$FILE" "$TEMP"; then