thumb: prefer progressive jpeg encoding

Intermediate rendering for faster results, and overall smaller file sizes
similar (if not identical) to jpegtran -optimize or PageSpeed.

diff --git a/thumb/index.php b/thumb/index.php
index fbea220b2bf7d48f5b0ae556862063c30271a816..5291047fc5fd422d93df89387141539f1999e066 100644 (file)
--- a/thumb/index.php
+++ b/thumb/index.php
@@ -90,6 +90,7 @@ function mkthumb_exec($source, $target, $width, $height)
                '-delete', '1--1',
                '-trim',
                '-background', 'white', '-layers', 'flatten',
+               '-interlace', 'plane', # progressive
                '-resize', "${width}x${height}",
                '-quality', '90%',
                $source, "jpg:$target"