[#]: subject: "My favorite Linux commands for optimizing web images" [#]: via: "https://opensource.com/article/21/12/optimize-web-images-linux" [#]: author: "Ayush Sharma https://opensource.com/users/ayushsharma" [#]: collector: "lujun9972" [#]: translator: "geekpi" [#]: reviewer: " " [#]: publisher: " " [#]: url: " " My favorite Linux commands for optimizing web images ====== Generate resized and optimized images for thumbnails and banner images for the web. ![Digital creative of a browser on the internet][1] I used to stay away from images when working online. Handling and optimizing images can be both imprecise and time-consuming. Then I found some commands that changed my mind. To create web pages, I use Jekyll, so I've included that in the directions. However, these commands will also work with other static site generators. ### Image commands on Linux The commands that made all the difference for me are `optipng`, `jpegoptim`, and, of course, the venerable `imagemagick`. Together, they make handling images easy to manage or even automate. Here’s an overview of how I implemented my solution using these commands. I placed article images in my `static/images` folder. From there, I generated two copies of all PNG and JPG images: 1. A cropped thumbnail version measuring 422 by 316 2. A larger banner version, measuring 1024 by 768 Then I placed each copy (the thumbnail and the banner) into its own folder, and I leveraged Jekyll's custom variables for the folder paths. I outline each of these steps in greater detail below. #### Installation To follow along with my solution, be sure you have all the commands installed. On Linux, you can install `optipng`, `jpegoptim`, and `imagemagick` using your package manager. On Fedora, CentOS, Mageia, and similar: ``` $ sudo dnf install optipng jpegoptim imagemagick ``` On Debian, Elementary, Mint, and similar: ``` $ sudo apt install optipng jpegoptim imagemagick ``` On macOS, use [MacPorts][2] or [Homebrew][3]. ``` brew install optipng jpegoptim imagemagick ``` On Windows, use [Chocolatey][4]. ### Creating folders for thumbnails and banners After installing the commands, I created new folders under `static/images`. Generated thumbnails get placed into `img-thumbs`, and banners go in `img-normal`. ``` $ cd static/images $ mkdir -p img-thumbs img-normal ``` With the folders created, I copied all GIF, SVG, JPG, and PNG files to both folders. I use the GIFs and SVGs as-is for thumbnails and banner images. ``` $ cp content/*.gif img-thumbs/; cp content/*.gif img-normal/ $ cp content/*.svg img-thumbs/; cp content/*.svg img-normal/ $ cp content/*.jpg img-thumbs/; cp content/*.jpg img-normal/ $ cp content/*.png img-thumbs/; cp content/*.png img-normal/ ``` ### Processing thumbnails To resize and optimize the thumbnails, I use my three commands. I use the `mogrify` command from `ImageMagick` to resize the JPGs and PNGs. Since I want the thumbnails to be 422 by 316, the command looks like this: ``` $ cd img-thumbs $ mogrify -resize 422x316 *.png $ mogrify -format jpg -resize 422x316 *.jpg ``` Now I optimize the PNGs using `optipng` and the JPGs using `jpegoptim`: ``` $ for i in *.png; do optipng -o5 -quiet "$i"; done $ jpegoptim -sq *.jpg ``` In the above command: * For `optipng`, `-o5` switch sets the level of optimization, with 0 being the lowest. * For `jpegoptim`, `-s` strips all image metadata, and `-q` sets quiet mode. ### Processing banners I process the banner images in essentially the same way I process the thumbnails, aside from the dimensions, which are 1024 by 768 for banners. ``` $ cd .. $ cd img-normal $ mogrify -resize 1024x768 *.png $ mogrify -format jpg -resize 1024x768 *.jpg $ for i in *.png; do optipng -o5 -quiet "$i"; done $ jpegoptim -sq *.jpg ``` ### Configuring the paths in Jekyll The `img-thumbs` directory now contains my thumbnails. and `img-normal` contains the banners. To make my life easier, I set both of them to custom variables in my Jekyll `_config.yml`. ``` content-images-path: /static/images/img-normal/ content-thumbs-images-path: /static/images/img-thumbs/ ``` Using the variables is simple. When I want to display the thumbnail, I prepend `content-thumbs-images-path` to the image. When I want to display the full banner, I prepend `content-images-path`. ``` {% if page.banner_img %} <img src="{{ page.banner_img | prepend: site.content-images-path | \ prepend: site.baseurl | prepend: site.url }}" alt="Banner image for \ {{ page.title }}" /> {% endif %} ``` ### Conclusion There are several improvements I could make to my optimization commands. Using `rsync` to copy only changed files to `img-thumbs` and `img-normal` is one obvious improvement. That way, I'm not reprocessing files over and over again. Adding those commands to [Git pre-commit hooks][5] or a CI pipeline is another useful step. Resizing and optimizing images to reduce their size is a win for the user and the web as a whole. Maybe my next step for reducing image sizes will be [webp][6]. Fewer bytes transmitted over the wire means a lower carbon footprint, but that's another article. The UX victory is good enough for now. * * * _This article was originally posted on the [author's blog][7] and has been republished with permission._ -------------------------------------------------------------------------------- via: https://opensource.com/article/21/12/optimize-web-images-linux 作者:[Ayush Sharma][a] 选题:[lujun9972][b] 译者:[译者ID](https://github.com/译者ID) 校对:[校对者ID](https://github.com/校对者ID) 本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译,[Linux中国](https://linux.cn/) 荣誉推出 [a]: https://opensource.com/users/ayushsharma [b]: https://github.com/lujun9972 [1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/browser_web_internet_website.png?itok=g5B_Bw62 (Digital creative of a browser on the internet) [2]: https://opensource.com/article/20/11/macports [3]: https://opensource.com/article/20/6/homebrew-mac [4]: https://opensource.com/article/20/3/chocolatey [5]: https://opensource.com/life/16/8/how-construct-your-own-git-server-part-6 [6]: https://opensource.com/article/20/4/webp-image-compression [7]: https://www.ayushsharma.in/2021/11/optimising-jpg-and-png-images-for-a-jekyll-blog