sudo mogrify -resize 25% *.JPG
As I write these and motorcycle Posts for this site that often require fone pics to be uploaded to WordPress, I needed a way to reduce default Sony Arc S 5MP shots of up to 1MB size to a smaller upload size, for which I used MS Paint for years.
Now I am completely Windows free, I had to find an App that could do this without having the hassle of GIMP just for this one task - especially not to have to edit each pic individually as I did with MS Paint.
Mogrify fulfils this need perfectly and is part of the ImageMagick suite:
apt-get install imagemagick
mogrify(1) General Commands Manual mogrify(1)
mogrify - resize an image, blur, crop, despeckle, dither, draw on, flip, join, re-sam‐
ple, and much more. Mogrify overwrites the original image file, whereas, convert(1)
writes to a different image file.
mogrify [options] input-file
The mogrify program is a member of the ImageMagick(1) suite of tools. Use it to resize
an image, blur, crop, despeckle, dither, draw on, flip, join, re-sample, and much more.
This tool is similar to convert(1) except the original image file is overwritten with
any changes you request.
mogrify -resize 25% *.jpg
Within seconds it reduces the copied 100Andro default folder content from my fone to 25% original size as you watch:
Now they are much quicker to upload to Post, and for you viewers to DL from the site pages.
You can explore the other switches mentioned in the man page overview if you have any other edit requirements.
This makes reviewing photos and writing Posts SO much quicker, as they also view quicker in the default Gnome Image Viewer for checking with the left/right keys, then deleting unwanted pics for Post planning before uploading using Shift+Del: