Base64 image not appearing in `pdf_document`

[averissimo]

Embededed base64 images are not properly rendered in pdf outputs.

note: the image is properly shown on other formats: html, rtf, word, odt

Rmd minimal example file:

---
title: Base64 test
---

There should be an image below.

![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAFUlEQVR42mP8z8BQz0AEYBxVSF+FABJADveWkH6oAAAAAElFTkSuQmCC)

There should be an image above.

When rendering via rmarkdown::pdf_document() it fails to produce the image.

rmarkdown::render("remove_me.Rmd", output_format = rmarkdown::pdf_document(), clean = FALSE, quiet = FALSE)

session info (click here to expand)

xfun::session_info('rmarkdown')
#> R version 4.5.2 (2025-10-31)
#> Platform: x86_64-pc-linux-gnu
#> Running under: Ubuntu 25.04
#> 
#> Locale:
#>   LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
#>   LC_TIME=en_IE.UTF-8        LC_COLLATE=en_US.UTF-8    
#>   LC_MONETARY=en_IE.UTF-8    LC_MESSAGES=en_US.UTF-8   
#>   LC_PAPER=en_IE.UTF-8       LC_NAME=C                 
#>   LC_ADDRESS=C               LC_TELEPHONE=C            
#>   LC_MEASUREMENT=en_IE.UTF-8 LC_IDENTIFICATION=C       
#> 
#> Package version:
#>   base64enc_0.1.3   bslib_0.9.0       cachem_1.1.0      cli_3.6.5        
#>   digest_0.6.37     evaluate_1.0.3    fastmap_1.2.0     fontawesome_0.5.3
#>   fs_1.6.6          glue_1.8.0        graphics_4.5.2    grDevices_4.5.2  
#>   highr_0.11        htmltools_0.5.8.1 jquerylib_0.1.4   jsonlite_2.0.0   
#>   knitr_1.50        lifecycle_1.0.4   memoise_2.0.1     methods_4.5.2    
#>   mime_0.13         R6_2.6.1          rappdirs_0.3.3    rlang_1.1.6      
#>   rmarkdown_2.30    sass_0.4.10       stats_4.5.2       tinytex_0.57     
#>   tools_4.5.2       utils_4.5.2       xfun_0.52         yaml_2.3.10      
#> 
#> Pandoc version: 3.1.11.1

Checklist

When filing a bug report, please check the boxes below to confirm that you have provided us with the information we need. Have you:

• formatted your issue so it is easier for us to read?

• included a minimal, self-contained, and reproducible example?

• pasted the output from xfun::session_info('rmarkdown') in your issue?

• upgraded all your packages to their latest versions (including your versions of R, the RStudio IDE, and relevant R packages)?

• installed and tested your bug with the development version of the rmarkdown package using remotes::install_github("rstudio/rmarkdown") ? (yup, same problem)