title: `ggsave` jpg reversed black-white values with `theme_minimal()`
body: <p>When I save a ggplot image with <code>theme_minimal</code> the black and white values are reversed in a photo negative like effect. This does not occur if I do not use a theme nor does it occur with theme_bw. It also does not occur when saving to <code>.pdf</code> or <code>.png</code>. I have tested and this occurs when running in RStudio, R GUI, or through the terminal. I'm running R version 4.0.2 on Mac OS 10.15.7.</p>
  <p>I would greatly appreciate any insight into debugging this. The behavior has persisted for several weeks across multiple full system restarts.</p>
  <pre><code>library(ggplot2) 
  ggplot(diamonds, aes(x = cut, y = clarity)) + 
    geom_point() + 
    theme_minimal() 
  
  ggsave(&quot;test_minimal.jpg&quot;)
  
  </code></pre>
  <p><img src="https://i.stack.imgur.com/EG8Up.jpg" alt="plot saved as photo negative" /></p>