Also have a look at FIJI (FIJI Is Just ImageJ) as it's emminently scriptable, so I'm told...
On 14 May 2017 at 20:29, Ray via luv-main <[email protected]> wrote: > On 14.05.2017 17:55, Mark Trickett via luv-main wrote: > >> Hello All, >> >> I am wanting to cut the file size of photos from my phone. I have >> tried opening in GIMP, but takes a bit of mousing and clicking around, >> and even saving/exporting several times to get the size down. I think >> the imagemagik suite should be able to do, but my reading of the man >> pages does not make it apparent to me. They talk of resizing, but it >> looks like the linear extent, rather than loosing some detail of the >> same extent of image. I would appreciate any contributions. >> >> regards, >> >> Mark Trickett >> _______________________________________________ >> luv-main mailing list >> [email protected] >> https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-mainT >> > > To scale an image in gimp load the image go to menu item "image>Scale > Image" > type in size, press scale. Examine the result. To save use menu item > "File>Export As..." > Close file, a box will come to save or discard file, press discard. > > If only doing a small number of images (below say 20) I use this > particularly if accurate size is important, say for desktop backgrounds.. > > On the command line when doing work on a lot of images consider the Netpbm > tools, this is a large set of command line tools that will allow one to do > almost ANYTHING with images on the command line, For scaling images > "pnmscale" does the job..... > Note: This is from an uptodate version of Netpbm, I believe the one in > Debian is VERY old. > > > pnmscale(1) General Commands Manual > pnmscale(1) > > NAME > pnmscale - scale a portable anymap > > SYNOPSIS > pnmscale scale_factor [pnmfile] > pnmscale -reduce reduction_factor [pnmfile] > pnmscale [{-xsize=cols | -width=cols | -xscale=factor}] > [{-ysize=rows | -height=rows | > -yscale=factor}] [pnmfile] > pnmscale -xysize cols rows [pnmfile] > pnmscale -pixels n [pnmfile] > > Miscellaneous options: > -verbose -nomix > > Minimum unique abbreviation of option is acceptable. You may use > double hypens instead of > single hyphen to denote options. You may use white space in place of > the equals sign to > separate an option name from its value. > > DESCRIPTION > Reads a PBM, PGM, or PPM image as input, scales it by the specified > factor or factors and > produces a PGM or PPM image as output. If the input file is in > color (PPM), the output > will be too, otherwise it will be grayscale (PGM). This is true even > if the input is a > black and white bitmap (PBM), because the process of scaling can > turn a combination of > black and white pixels into a gray pixel. > > If you want PBM output, use pgmtopbm to convert pnmscale's output to > PBM. Also consider > pbmreduce. > > You can both enlarge (scale factor > 1) and reduce (scale factor < 1). > > When you specify an absolute size or scale factor for both > dimensions, pnmscale scales > each dimension independently without consideration of the aspect ratio. > > If you specify one dimension as a pixel size and don't specify the > other dimension, pnm- > scale scales the unspecified dimension to preserve the aspect ratio. > > If you specify one dimension as a scale factor and don't specify the > other dimension, pnm- > scale leaves the unspecified dimension unchanged from the input. > > If you specify the scale_factor parameter instead of dimension options, > that is the scale > factor for both dimensions. It is equivalent to -xscale=scale_factor > -yscale=scale_factor > . > > Specifying the -reduce reduction_factor option is equivalent to > specifying the scale_fac- > tor parameter, where scale_factor is the reciprocal of reduction_factor. > > -xysize specifies a bounding box. pnmscale scales the input image > to the largest size > that fits within the box, while preserving its aspect ratio. > > -pixels specifies a maximum total number of output pixels. pnmscale > scales the image down > to that number of pixels. If the input image is already no more > than that many pixels, > pnmscale just copies it as output; pnmscale does not scale up with > -pixels. > > ............................ much text cut out.................. > > > _______________________________________________ > luv-main mailing list > [email protected] > https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-main > -- Dr Paul van den Bergen
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