imgp - Man Page

Resize, rotate JPEG and PNG images.

Examples (TL;DR)


imgp [Options] [PATH [PATH ...]]


imgp is a multiprocessing command line image resizer and rotator for JPEG and PNG images.


 * 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

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

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.


-h,  --help

Show help text and exit.

-x,  --res=res

Output resolution in HRESxVRES or percentage.

-o,  --rotate=deg

Rotate clockwise by a specified angle (in degrees). Negative inputs rotate anti-clockwise. Rotation by 0 degree is not allowed.

-a,  --adapt

Adapt to specified resolution considering the orientation of the image. Disabled by default.

-c,  --convert

Convert PNG images to JPEG to save on space. The output image is saved with '.jpg' extension.

-e,  --eraseexif

Erase EXIF metadata of JPEG images. Preserved by default.

-f,  --force

Force to the exact specified resolution. Disabled by default.

-H,  --hidden

Include hidden (dot) files. By default hidden files are skipped. -i, --includeimgp Process _IMGP files. Risky due to potential race conditions.

-k,  --keep

Do not process if image hres or vres matches specified hres or vres, or --res is 100. However, PNG images are converted to JPEG if --convert option is specified and JPEG images are made progressive is --progressive option is specified.

-n,  --enlarge

Enlarge smaller images. By default smaller images are not scaled if specified resolution is greater.

-N --nearest

Use nearest neighbour interpolation for PNG images instead of default antialias.

-p,  --optimize

Optimize output images using PIL library optimization algorithm. Disabled by default.

-P,  --progressive

Save all output JPEG images as progressive, even if the source is not.

-q,  --quality=N

Save the image with a specified quality factor N (scale 1-95, default 75). JPEG only.

-m,  --mute

Do not show any operational output.

-M,  --minresres

minimum resolution in HxV or percentage of --res to resize

-r,  --recurse

Recursively process sub-directories. By default only the specified directory is processed. Symbolic links are ignored to avoid recursive loops.

-s,  --size=byte

Minimum size in bytes required to process an image. Acts as a guard against processing low-resolution images. Default 1024 bytes.

-w,  --overwrite

Overwrite the source images. By default an output image is saved with _IMGP appended to the source image name.
NOTE: If overwrite and convert options are used together, source PNG images are deleted.

-d,  --debug

Enable debugging.


  1. Convert some images and directories:

    $ imgp -x 1366x768 ~/ ~/Pictures/image3.png ~/Downloads/
    3840x2160 -> 1365x768
    11104999 bytes -> 1486426 bytes
    2048x1365 -> 1152x768
    224642 bytes -> 31421 bytes
    1920x1080 -> 1365x768
    2811155 bytes -> 1657474 bytes
    2048x1365 -> 1152x768
    224642 bytes -> 31421 bytes
  2. Scale an image by 75% and overwrite the source image:

    $ imgp -x 75 -w ~/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...
    1366x911 -> 800x534
    69022 bytes -> 35123 bytes
    1050x1400 -> 800x1067
    458092 bytes -> 78089 bytes
  6. Process images greater than 50KiB only:

    $ imgp -wrackx 1366x1000 -s 51200
  7. Generate a 64px adaptive thumbnail of the last modified file in the current dir:

    #!/usr/bin/env sh
    thumb64 ()
        pop=$(ls -1t | head -1)
        imgp -acx 64x64 "$pop"


Arun Prakash Jana <>


Reporting Bugs


Copyright © 2016-2023 Arun Prakash Jana <>

License GPLv3+: GNU GPL version 3 or later <>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


10 Sep 2023 Version 2.9