Error(s) in re-building vignettes:
--- re-building 'batch-mode.Rmd' using rmarkdown
--- finished re-building 'batch-mode.Rmd'

--- re-building 'linescan-data.Rmd' using rmarkdown
--- finished re-building 'linescan-data.Rmd'

--- re-building 'single-images.Rmd' using rmarkdown
trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/colorspace_1.4-1.zip'
Content type 'application/zip' length 2550276 bytes (2.4 MB)
==================================================
downloaded 2.4 MB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/farver_2.0.3.zip'
Content type 'application/zip' length 1912052 bytes (1.8 MB)
==================================================
downloaded 1.8 MB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/labeling_0.3.zip'
Content type 'application/zip' length 62937 bytes (61 KB)
==================================================
downloaded 61 KB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/munsell_0.5.0.zip'
Content type 'application/zip' length 245575 bytes (239 KB)
==================================================
downloaded 239 KB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/RColorBrewer_1.1-2.zip'
Content type 'application/zip' length 55569 bytes (54 KB)
==================================================
downloaded 54 KB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/viridisLite_0.3.0.zip'
Content type 'application/zip' length 60727 bytes (59 KB)
==================================================
downloaded 59 KB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/isoband_0.2.0.zip'
Content type 'application/zip' length 2899884 bytes (2.8 MB)
==============================================
downloaded 2.6 MB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/scales_1.1.0.zip'
Content type 'application/zip' length 554678 bytes (541 KB)
==================================================
downloaded 541 KB

trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.6/ggplot2_3.3.0.zip'
Content type 'application/zip' length 4021900 bytes (3.8 MB)
==================================================
downloaded 3.8 MB

Quitting from lines 15-19 (single-images.Rmd) 
Error: processing vignette 'single-images.Rmd' failed with diagnostics:
cannot open the connection
--- failed re-building 'single-images.Rmd'

SUMMARY: processing the following file failed:
  'single-images.Rmd'

Error: Vignette re-building failed.
Execution halted