diff --git a/inst/BS5/assets/pkgdown.scss b/inst/BS5/assets/pkgdown.scss
index 86d40cc6b..51f776155 100644
--- a/inst/BS5/assets/pkgdown.scss
+++ b/inst/BS5/assets/pkgdown.scss
@@ -224,6 +224,7 @@ body > .container .row {
 main img {
   max-width: 100%;
   height: auto;
+  background-color: white;
 }
 main table {
   display: block;
@@ -311,6 +312,7 @@ img.logo {
   float: right;
   width: 100px;
   margin-left: 30px;
+  background-color: transparent;
 }
 .template-home img.logo {
   width: 120px;
diff --git a/vignettes/test/rendering.Rmd b/vignettes/test/rendering.Rmd
index 11cc8506d..358badee5 100644
--- a/vignettes/test/rendering.Rmd
+++ b/vignettes/test/rendering.Rmd
@@ -25,6 +25,14 @@ Yay[^footnote]
 plot(1:10)
 ```
 
+Use a white background for base plots in dark mode.
+
+```{r}
+#| fig.alt: Test plot with white background
+par(bg = 'white')
+plot(50:10)
+```
+
 ## External files
 
 ```{r}