CompressUploads

This extension uses various techniques to reduce the size of uploaded files. Made for ULYSSIS VZW by Joachim Vandersmissen.

Features

• Compress PDF files using qpdf.
• Convert inefficient file formats (by default: BMP and TIFF) to PNG files.
• Compress PNG files using configurable levels and filters.
• Compress JPG files to configurable quality.
• Automatically resize images exceeding a maximum width or height (or both).
• Strip all EXIF data (orientation data will be processed, and ICC profiles are kept).

Installation

• Install qpdf for PDF compression.
• Install ImageMagick and Imagick for image processing.
• Download the latest release, and put the CompressUploads folder in the extensions directory.
• Add the following to LocalSettings.php:

wfLoadExtension( 'CompressUploads' );

Configuration

As usual, configuration options can be added to LocalSettings.php using global variables.

Option	Value	Default Value	Description
$wgCUCompressPdf	boolean	true	Whether PDF files should be compressed using qpdf. This technique uses PDF Object Streams, which means the compression will have the most effect on PDF files containing a lot of indirect objects.
$wgCUConvertImages	String[]	["image/bmp", "image/x-bmp", "image/x-ms-bmp", "image/tiff", "image/tiff-fx"]	The MIME types of all inefficient image file formats that should be converted to PNG.
$wgCUPngCompression	int	9	The PNG compression level (0-9). This compression is lossless and should not cause any artifacts.
$wgCUPngFilter	int	6	The PNG compression filter. For advanced users.
$wgCUJpgQuality	int	80	The JPG compression quality (0-100). This compression is lossy: lower quality levels will cause compression artifacts.
$wgCUMaxWidth	int	2000	The maximum image width in pixels, larger images will be scaled accordingly. If not set, image width is unlimited.
$wgCUMaxHeight	int	2000	The maximum image height in pixels, larger images will be scaled accordingly. If not set, image height is unlimited.
$wgCUStripExif	boolean	true	Whether EXIF data should be stripped from uploaded images.

Tips

• MediaWiki keeps temporary uploaded files in images/temp/. You could periodically delete these to free up space.
• MediaWiki keeps deleted uploaded files in images/deleted/. You could delete these, provided you are absolutely sure you won't have to 'undelete' them.
• The MediaWiki page Special:ListFiles shows every uploaded file on the wiki. These files can be sorted by size to quickly find out which files take up most space.
• If EXIF data is stripped, metadata such as camera brand, aspect ratio, location is also removed. A win for privacy!