When ImageMagick scales images it will copy any EXIF data unless told not to. The images on the willow site contained approximately 18K of EXIF data and this was being copied into the thumbnail variations.
eZ publish makes it easy to add filters for image variations. Simply add the following line to image.ini.append.php in your siteaccess file:
[ImageMagick]This will strip EXIF information for "small" image variations and can be added to others by simply adding the Filters line to the variations definition.
Filters=strip=+profile "*" +comment
Newer versions of ImageMagick have a -strip flag that will also remove EXIF data. To use this replace the [ImageMagick] section with:
[ImageMagick]This will work on all versions of eZ publish 3 that are using ImageMagick to create image variations.
This has reduced the page size of some of the willow collection pages from 856 kb to 168 kb !