vipsthumbnail man page
vipsthumbnail — make thumbnails of image files
vipsthumbnail [flags] imagefile1 imagefile2 ...
vipsthumbnail(1) processes each imagefile in turn, shrinking each image to fit within a 128 by 128 pixel square. The shrunk image is written to a new file named tn_imagefile.jpg. This program is typically faster and uses less memory than other image thumbnail programs.
$ vipsthumbnail fred.png jim.tif
will read image files fred.png and jim.tif and write thumbnails to the files tn_fred.jpg and tn_jim.jpg.
$ vipsthumbnail --size=64 -o thumbnails/%s.png fred.jpg
will read image file fred.jpg and write a 64 x 64 pixel thumbnail to the file thumbnails/fred.png.
- -s N, --size=N
Set the output thumbnail size to N x N pixels.
You can use "MxN" to specify a rectangular bounding box. The image is shrunk so that it just fits within this area, images which are smaller than this are expanded.
Use "xN" or "Mx" to just resize on one axis.
Append "<" to only resize if the input image is smaller than the target, append ">" to only resize if the input image is larger than the target.
- -o FORMAT, --output=FORMAT
Set the output format string. The input filename has any file type suffix removed, then that value is substitued into FORMAT replacing %s. If FORMAT is a relative path, the name of the input directory is prepended. In other words, any path in FORMAT is relative to the directory of the current input file.
The default value is tn_%s.jpg meaning JPEG output, with tn_ prepended. You can add format options too, for example tn_%s.jpg[Q=20] will write JPEG images with Q set to 20.
- -e PROFILE, --eprofile=PROFILE
Export thumbnails with this ICC profile. Images are only colour-transformed if there is both an output and an input profile available. The input profile can either be embedded in the input image or supplied with the --iprofile option.
- -i PROFILE, --iprofile=PROFILE
Import images with this ICC profile, if no profile is embdedded in the image. Images are only colour-transformed if there is both an output and an input profile available. The output profile should be supplied with the --oprofile option.
- -c, --crop
Crop the output image down. The image is shrunk so as to completely fill the bounding box in both axes, then any excess is cropped off.
- -d, --delete
Delete the output profile from the image. This can save a small amount of space.
- -t, --rotate
Auto-rotate images using EXIF orientation tags.
- -a, --linear
Shrink images in linear light colour space. This can be much slower.
returns 0 on success and non-zero on error. Error can mean one or more conversions failed.