resize jpg

Ever wanted to resize a jpg image and getting awful results when just directly resizing the jpg? Why doesn't that work? Well, jpg are not made to be resized without quality loss. But png images can be resized without (visible) quality loss. So what about converting the jpg to a png, then resizing the png, and then converting the resized png back to a jpg of the same dimensions. Problem solved.

That's what this cli app is for. And you can convert an entiry directory of jpg files in one go!

Install

you need imagemagick for this.

brew install imagemagick # for Mac os

npm install -g resize-jpg

Usage

Say I am in the terminal in my home directory. In my home directory I have a folder named my_jpg_files with jpg images of various dimensions that I want to resize (all of them) to width 700px and height 800px and I want to place the converted jpg files in a folder named my_converted_jpg_files.

To do the above do (when in your home directory in the terminal):

resize-jpg -i my_jpg_files -o my_converted_jpg_files -w 700 -h 800

for help type

resize-jpg
# OR
resize-jpg -h
# OR
resize-jpg --help

What it does under the hood

it loops over all jpg files found in the input directory and uses imagemagick to for each file convert the file:

1. from jpg original size to png original size
2. from png original size to png wanted size
3. from png wanted size to jpg wanted size

TODO

• [ ] use jimp pure-js image conversion module, instead of imagemagick