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.
For example:
$ 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.
-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. 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.
-p I, --interpolator=I
Resample with interpolator I. Use vips --list classes to see a list of valid interpolators. The default is bilinear.
-r, --sharpen=none|mild|MASKFILE
Images can look a little soft after shrinking. This option lets you specify a sharpening mask. Use "none" to disable sharpening, or "mild" to sharpen lightly, or give the filename of a custom mask file to use. The default is "mild". The built-in mild sharpen mask is:
3 3 24 0 -1 -1 -1 -1 32 -1 -1 -1 -1
-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 axies, then any excess is cropped off.
-d, --delete
Delete the output profile from the image. This can save a small amount of space.
-v, --verbose
vipsthumbnail(1) normally runs silently, except for warning and error messages. This option makes it print a list of the operations it performs on each image.
returns 0 on success and non-zero on error.