How to set size for local image using knitr for markdown?

by

The question is old, but still receives a lot of attention. As the existing answers are outdated, here a more up-to-date solution:

Resizing local images

As of knitr 1.12, there is the function include_graphics. From ?include_graphics (emphasis mine):

The major advantage of using this function is that it is portable in the sense that it works for all document formats that knitr supports, so you do not need to think if you have to use, for example, LaTeX or Markdown syntax, to embed an external image. Chunk options related to graphics output that work for normal R plots also work for these images, such as out.width and out.height.

Example:

```{r, out.width = "400px"}
knitr::include_graphics("path/to/image.png")
```

Advantages:

  • Over agastudy’s answer: No need for external libraries or for re-rastering the image.
  • Over Shruti Kapoor’s answer: No need to manually write HTML. Besides, the image is included in the self-contained version of the file.

Including generated images

To compose the path to a plot that is generated in a chunk (but not included), the chunk options opts_current$get("fig.path") (path to figure directory) as well as opts_current$get("label") (label of current chunk) may be useful. The following example uses fig.path to include the second of two images which were generated (but not displayed) in the first chunk:

```{r generate_figures, fig.show = "hide"}
library(knitr)
plot(1:10, col = "green")
plot(1:10, col = "red")
```

```{r}
include_graphics(sprintf("%sgenerate_figures-2.png", opts_current$get("fig.path")))
```

The general pattern of figure paths is [fig.path]/[chunklabel]-[i].[ext], where chunklabel is the label of the chunk where the plot has been generated, i is the plot index (within this chunk) and ext is the file extension (by default png in RMarkdown documents).

More Related Contents:

  1. Figure position in markdown when converting to PDF with knitr and pandoc
  2. Set margin size when converting from Markdown to PDF with pandoc
  3. Create parametric R markdown documentation?
  4. Changing image size in Markdown
  5. How to combine two RMarkdown (.Rmd) files into a single output?
  6. How to source R Markdown file like `source(‘myfile.r’)`?
  7. Programmatically creating Markdown tables in R with KnitR
  8. R Markdown – variable output name
  9. generate markdown comments within for loop
  10. How do I display local image in markdown?
  11. R – Markdown avoiding package loading messages
  12. Plot size and resolution with R markdown, knitr, pandoc, beamer
  13. R: Creating graphs where the nodes are images
  14. New R-Studio version 0.98.932 deletes .md file – how to prevent?
  15. R: add alpha-value to png-image
  16. Knit one markdown file to two output files
  17. YAML current date in rmarkdown
  18. Convert RGBA color to RGB
  19. Image fingerprint to compare similarity of many images
  20. Rstudio rmarkdown: both portrait and landscape layout in a single PDF
  21. Using stargazer with Rstudio and Knitr
  22. Storing images in NoSQL stores
  23. Extracting image from PDF with /CCITTFaxDecode filter
  24. In `knitr` how can I test for if the output will be PDF or word?
  25. how to create a loop that includes both a code chunk and text with knitr in R
  26. How to stop bookdown tables from floating to bottom of the page in pdf?
  27. Unicode with knitr and Rmarkdown
  28. Loop in R markdown
  29. Is it OK to HTTP redirect images?
  30. How to convert an Image to UIImage?

Leave a Comment