Compressing Images in R

Yihui Xie announces a new package:

Last month, @bastistician opened an issue on the litedown repo pointing out that knitr has a hook_pngquant() function for compressing PNG plots from code chunks, but litedown lacks such a feature. He included a reasonable workaround—calling system2("pngquant", ...) with litedown::get_context("plot_files") in a chunk at the end of the vignette. It shrank his vignette from 80 KB to 54 KB, which is a 33% reduction. Not bad.

The catch, of course, is that it requires pngquant to be installed on the system. For R users, installing a system binary is more friction than it sounds: it is brew install pngquant on macOS, a separate package manager invocation on Linux, and hunting down a standalone executable on Windows. If you maintain a package that others will build, you are now asking all of them to do this—for every machine they use. By contrast, install.packages("tinyimg") works the same way everywhere, which is the kind of simplicity that makes a tool actually get used.

This is why I created tinyimg.

Read on for more details about how tinyimg works, how well it compresses, and how it integrates with litedown.