:camera_flash: Fast batch image resizer and rotator

jarun, updated 🕥 2023-02-19 03:07:38


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Watch imgp resize a directory of images in lightning speed!

imgp is a command line image resizer and rotator for JPEG and PNG images. It can resize (or thumbnail) and rotate thousands of images in a go, at lightning speed, while saving significantly on storage.

Powered by multiprocessing, SIMD parallelism (thanks to the Pillow-SIMD library), an intelligent adaptive algorithm, recursive operations, shell completion scripts, EXIF preservation (and more), imgp is a very flexible utility with well-documented easy to use options.

imgp intends to be a stronger replacement of the Nautilus Image Converter extension, not tied to any file manager and way faster. On desktop environments (like Xfce or LxQt) which do not integrate Nautilus, imgp will save your day. File manager nnn provides a script to batch resize images with imgp.

Table of Contents


  • resize by percentage or resolution
  • rotate clockwise by specified angle
  • adaptive resize considering orientation
  • brute force to a resolution
  • optimize images to save more space
  • limit processing by minimum image size
  • convert PNG to JPEG
  • erase exif metadata
  • specify output JPEG image quality
  • force smaller to larger resize
  • process directories recursively
  • overwrite source image option
  • completion scripts for bash, fish, zsh
  • minimal dependencies

Adaptive mode

  • If the specified and image orientations are same [(H >= V and h > v) or (H < V and h < v)], the image is resized with the longer specified side as reference.
  • In case of cross orientation [(H >= V and h <= v) or (H < V and h >= v)], the image is resized with the shorter specified side as reference. Same as non-adaptive.

For example, if an image has a resolution of 2048x1365 and is being resized to 1366x768:

  • In regular mode (default), output image resolution will be 1152x768
  • In adaptive mode, output image resolution will be 1366x910


imgp could resize 8823 images (approx. 4.5GB in size) of mixed resolutions (high to regular) stored in a USB 2.0 external hard disk at an adaptive resolution of 1366x1000 in around 8 minutes. The resulting size was 897MB (approx. 20%).

imgp uses Python PIL/Pillow library. Nautilus Image Converter calls the convert utility from ImageMagick. For a comparative benchmark, head here.



imgp requires Python 3.7 or later.

To install PIL library on Ubuntu, run:

$ sudo apt-get install python3-pil

or, using pip3:

$ sudo pip3 install pillow

pillow can be replaced by pillow-simd on SIMD processors.

From a package manager

Install imgp from your package manager. If the version available is dated try an alternative installation method.

Packaging status (expand)

Packaging status

Unlisted packagers:

Homebrew TAP (brew install jarun/imgp/imgp)
PyPI (pip3 install imgp)
Source Mage (cast imgp)

Release packages

Packages for Arch Linux, CentOS, Debian, Fedora, openSUSE Leap and Ubuntu are available with the latest stable release.

From source

If you have git installed, clone this repository. Otherwise download the latest stable release or development version (risky).

Install to default location (/usr/local):

$ sudo make install

To remove, run:

$ sudo make uninstall

PREFIX is supported, in case you want to install to a different location.

Running standalone

imgp is a standalone utility. From the containing directory, run:

$ ./imgp

Shell completion

Shell completion scripts for Bash, Fish and Zsh can be found in respective subdirectories of auto-completion/. Please refer to your shell's manual for installation instructions.


cmdline options

``` usage: imgp [-h] [-x res] [-o deg] [-a] [-c] [-e] [-f] [-H] [-i] [-k] [-m] [-M res] [-n] [-N] [-O] [-P] [-q N] [-r] [-s byte] [-w] [-d] [PATH [PATH ...]]

Resize, rotate JPEG and PNG images.

positional arguments: PATH source file or dir [default: current dir]

optional arguments: -h, --help show this help message and exit -x res, --res res output resolution in HxV or percentage -o deg, --rotate deg rotate clockwise by angle (in degrees) -a, --adapt adapt to resolution by orientation [default: off] -c, --convert convert PNG to JPG format [default: off] -e, --eraseexif erase exif metadata [default: off] -f, --force force to exact specified resolution [default: off] -H, --hidden include hidden (dot) files [default: off] -i, --includeimgp re-process _IMGP files. * RISKY: refer to docs -k, --keep skip (honors -c or --pr) images matching specified H or V or --res=100 [default: off] -m, --mute operate silently [default: informative] -M res, --minres res min resolution in HxV or percentage of --res to resize -n, --enlarge enlarge smaller images [default: off] -N, --nearest use nearest neighbour interpolation for PNG [default: antialias] -O, --optimize optimize the output images [default: off] -P, --progressive save JPEG images as progressive [default: off] -q N, --quality N quality factor (N=1-95, JPEG only) [default: 75] -r, --recurse process non-symbolic dirs recursively [default: off] -s byte, --size byte minimum size to process an image [default: 1024] -w, --overwrite overwrite source images [default: off] -d, --debug enable debug logs [default: off] ```

Operational notes

  • Multiple files and directories can be specified as source. If PATH is omitted, the current directory is processed.
  • Output image names are appended with _IMGP if --overwrite option is not used. By default _IMGP files are not processed. Doing so may lead to potential race conditions when --overwrite option is used.
  • PNG files with lower target hres/vres are not converted (even if --convert is used). Run imgp --convert (*.png) separately to convert those.
  • Resize and rotate are lossy operations. For additional reductions in size try --optimize and --eraseexif options.
  • Option --optimize is slower, the encoder makes an extra pass over the image in order to select optimal encoder settings.
  • Progressive JPEG images are saved as progressive.


  1. Convert some images and directories:

    $ imgp -x 1366x768 ~/ ~/Pictures/image3.png ~/Downloads/ /home/testuser/image1.png 3840x2160 -> 1365x768 11104999 bytes -> 1486426 bytes

    /home/testuser/image2.jpg 2048x1365 -> 1152x768 224642 bytes -> 31421 bytes

    /home/testuser/Pictures/image3.png 1920x1080 -> 1365x768 2811155 bytes -> 1657474 bytes

    /home/testuser/Downloads/image4 2048x1365 -> 1152x768 224642 bytes -> 31421 bytes

  2. Scale an image by 75% and overwrite the source image:

    $ imgp -x 75 -w ~/image.jpg /home/testuser/image.jpg 1366x767 -> 1025x575 120968 bytes -> 45040 bytes

  3. Rotate an image clockwise by 90 degrees:

    $ imgp -o 90 ~/image.jpg 120968 bytes -> 72038 bytes

  4. Adapt the images in the current directory to 1366x1000 resolution. Visit all directories recursively, overwrite source images, ignore images with matching hres or vres but convert PNG images to JPEG.

    $ imgp -x 1366x1000 -wrack

  5. Set hres=800 and adapt vres maintaining the ratio.

    $ imgp -x 800x0 Source omitted. Processing current directory...

    ./image1.jpg 1366x911 -> 800x534 69022 bytes -> 35123 bytes

    ./image2.jpg 1050x1400 -> 800x1067 458092 bytes -> 78089 bytes

  6. Process images greater than 50KiB only:

    $ imgp -wrackx 1366x1000 -s 51200

  7. Generate a 64px adapative thumbnail of the last modified file in the current dir:

    #!/usr/bin/env sh

    thumb64 () { pop=$(ls -1t | head -1) imgp -acx 64x64 "$pop" }


  1. Copyright © 2016-2023 Arun Prakash Jana
  2. Ananya Jana


imgp v2.8 2020-11-30 19:54:47

  • Option -M to specify minimum resolution of iamges to process
  • Option -H (process hidden files) replaces -d
  • Option -d (debug mode) replaces -z
  • Option -N and --nearest (nearest neighbour for PNG) replace --nn
  • Option -P (save JPEG as progressive) replaces --pr

Donate via PayPal!

imgp v2.7 2019-12-21 09:30:02

  • Code lint fixes
  • Package uploaded to PyPI
  • New auto-generated packages for - CentOS, Debian, Fedora
  • Update copyright year

imgp v2.6 2018-10-20 16:21:04

What's in?

  • Support for progressive JPEG
  • Some bug fixes and documentation update
  • Package generation for some more distros

imgp v2.5 2018-02-19 03:29:54

What's in?

  • New option --nn to use nearest neighbour interpolation for PNG files
  • Identify Multi Picture Object (MPO) files

imgp v2.4.1 2017-08-29 16:11:52

What's in?

  • Integrated with PackageCore to auto-generate packages in Travis CI.

This is a maintenance release to make packages for multiple distros available.

imgp v2.4 2017-07-24 13:12:50

What's in?

  • New option --quality (-q) to specify quality [default: 75]
  • Homebrew tap for OS X users [brew install jarun/imgp/imgp]
  • Option --quiet is now --mute
  • Use global fill color white (#ffffff) for alpha channel

Writing terminal utilities (often GUI-integrated) for efficient workflows. If you find them useful, please sponsor.

GitHub Repository

image-processing image-compression image-manipulation image-optimization image-resize image-rotate multiprocessing standalone command-line terminal console image-resizer image-resolution cli