Utilities for archiving photos for saving to long term storage or serving over the web. The goals are:
- Use a common, well supported format (JPEG)
- Minimize storage space and cost
- Identify duplicates / similar photos
- Command line utilities and scripts
- Simple options and useful help
- Good quality output via sane defaults
Contributions to this project are very welcome.
If you are looking for an easy way to run these utilities in parallel over many files to utilize all CPU cores, please also download Ladon or GNU Parallel. You can then use the
jpeg-archive command below or use
ladon directly. Example:
# Re-compress JPEGs and replace the originals ladon "Photos/**/*.jpg" -- jpeg-recompress FULLPATH FULLPATH # Re-compress JPEGs into the new directory 'Comp' ladon -m Comp/RELDIR "Photos/**/*.jpg" -- jpeg-recompress FULLPATH Comp/RELPATH
The following utilities are part of this project. All of them accept a
--help parameter to see the available options.
Compress RAW and JPEG files in a folder utilizing all CPU cores. This is a simple shell script that uses the utilities below. It requires:
- a POSIX-compatible shell such as Bash
- Ladon or GNU Parallel
- jpeg-recompress (part of this project)
# Compress a folder of images cd path/to/photos jpeg-archive # Custom quality and metric jpeg-archive --quality medium --method smallfry
Compress JPEGs by re-encoding to the smallest JPEG quality while keeping perceived visual quality the same and by making sure huffman tables are optimized. This is a lossy operation, but the images are visually identical and it usually saves 30-70% of the size for JPEGs coming from a digital camera, particularly DSLRs. By default all EXIF/IPTC/XMP and color profile metadata is copied over, but this can be disabled to save more space if desired.
There is no need for the input file to be a JPEG. In fact, you can use
jpeg-recompress as a replacement for
cjpeg by using PPM input and the
The better the quality of the input image is, the better the output will be.
Some basic photo-related editing options are available, such as removing fisheye lens distortion.
Below are two 100% crops of Nikon's D3x Sample Image 2. The left shows the original image from the camera, while the others show the output of
jpeg-recompress with the
medium quality setting and various comparison methods. By default SSIM is used, which lowers the file size by 88%. The recompression algorithm chooses a JPEG quality of 80. By comparison the
veryhigh quality setting chooses a JPEG quality of 93 and saves 70% of the file size.
Why are they different sizes? The default quality settings are set to average out to similar visual quality over large data sets. They may differ on individual photos (like above) because each metric considers different parts of the image to be more or less important for compression.
Image Comparison Metrics
The following metrics are available when using
jpeg-recompress. SSIM is the default.
||Mean pixel error (as used by imgmin)|
||Structural similarity DEFAULT|
||Multi-scale structural similarity (slow!) (2008 paper)|
||Linear-weighted BBCQ-like (original project, 2011 BBCQ paper)|
Note: The SmallFry algorithm may be patented so use with caution.
The JPEG format allows for subsampling of the color channels to save space. For each 2x2 block of pixels per color channel (four pixels total) it can store four pixels (all of them), two pixels or a single pixel. By default, the JPEG encoder subsamples the non-luma channels to two pixels (often referred to as 4:2:0 subsampling). Most digital cameras do the same because of limitations in the human eye. This may lead to unintended behavior for specific use cases (see #12 for an example), so you can use
--subsample disable to disable this subsampling.
# Default settings jpeg-recompress image.jpg compressed.jpg # High quality example settings jpeg-recompress --quality high --min 60 image.jpg compressed.jpg # Slow high quality settings (3-4x slower than above, slightly more accurate) jpeg-recompress --accurate --quality high --min 60 image.jpg compressed.jpg # Use SmallFry instead of SSIM jpeg-recompress --method smallfry image.jpg compressed.jpg # Use 4:4:4 sampling (disables subsampling). jpeg-recompress --subsample disable image.jpg compressed.jpg # Remove fisheye distortion (Tokina 10-17mm on APS-C @ 10mm) jpeg-recompress --defish 2.6 --zoom 1.2 image.jpg defished.jpg # Read from stdin and write to stdout with '-' as the filename jpeg-recompress - - <image.jpg >compressed.jpg # Convert RAW to JPEG via PPM from stdin dcraw -w -q 3 -c IMG_1234.CR2 | jpeg-recompress --ppm - compressed.jpg # Disable progressive mode (not recommended) jpeg-recompress --no-progressive image.jpg compressed.jpg # Disable all output except for errors jpeg-recompress --quiet image.jpg compressed.jpg
Compare two JPEG photos to judge how similar they are. The
fast comparison method returns an integer from 0 to 99, where 0 is identical. PSNR, SSIM, and MS-SSIM return floats but require images to be the same dimensions.
# Do a fast compare of two images jpeg-compare image1.jpg image2.jpg # Calculate PSNR jpeg-compare --method psnr image1.jpg image2.jpg # Calculate SSIM jpeg-compare --method ssim image1.jpg image2.jpg
Create a hash of an image that can be used to compare it to other images quickly.
Ubuntu users can install via
sudo apt-get install build-essential autoconf pkg-config nasm libtool git clone https://github.com/mozilla/mozjpeg.git cd mozjpeg autoreconf -fiv ./configure --with-jpeg8 make sudo make install
Mac OS X
Mac users can install it via Homebrew:
brew install mozjpeg
pkg install mozjpeg git clone https://github.com/danielgtaylor/jpeg-archive.git cd jpeg-archive/ gmake sudo gmake install
Makefile should work with MinGW/Cygwin/etc and standard GCC. Patches welcome.
To get everything you need to build, install these:
Run Github for windows. In the settings, set Git Bash as the shell. Open Git Shell from the start menu.
# Update PATH to include MinGW/NASM bin folder, location on your system may vary export PATH=/c/mingw/mingw32/bin:/c/Program\ Files \(x68\)/nasm:$PATH # Build mozjpeg or download https://www.dropbox.com/s/98jppfgds2xjblu/libjpeg.a git clone https://github.com/mozilla/mozjpeg.git cd mozjpeg cmake -G "MSYS Makefiles" -D CMAKE_C_COMPILER=gcc.exe -D CMAKE_MAKE_PROGRAM=mingw32-make.exe -D WITH_JPEG8=1 mingw32-make cd .. # Build jpeg-archive git clone https://github.com/danielgtaylor/jpeg-archive cd jpeg-archive CC=gcc mingw32-make
JPEG-Archive should now be built.
Compiling (Linux and Mac OS X)
Makefile should work as-is on Ubuntu and Mac OS X. Other platforms may need to set the location of
libjpeg.a or make other tweaks.
Install the binaries into
sudo make install
Links / Alternatives
- JPEG-Archive is copyright © 2015 Daniel G. Taylor
- Image Quality Assessment (IQA) is copyright 2011, Tom Distler (http://tdistler.com)
- SmallFry is copyright 2014, Derek Buitenhuis (https://github.com/dwbuiten)
All are released under an MIT license.