diff --git a/R/hooks-html.R b/R/hooks-html.R
index 0cd63dd7dd..742e090ca3 100644
--- a/R/hooks-html.R
+++ b/R/hooks-html.R
@@ -64,6 +64,16 @@ hook_animation = function(options) {
   ), cap)
 }
 
+.img.id = function(options) {
+  sprintf(
+    'id="%s"',
+    paste0(
+      options$fig.lp, options$label,
+      if (options$fig.num > 1L && options$fig.show == 'asis') options$fig.cur
+    )
+  )
+}
+
 # a wrapper to upload an image and return the URL
 .upload.url = function(x) {
   opts_knit$get('upload.fun')(x)
diff --git a/R/hooks-md.R b/R/hooks-md.R
index 6319b1ceef..995ea306c4 100644
--- a/R/hooks-md.R
+++ b/R/hooks-md.R
@@ -63,8 +63,9 @@ hook_plot_md_base = function(x, options) {
     d1 = if (plot1) sprintf('<div class="figure"%s>\n', css_text_align(a))
     d2 = sprintf('<p class="caption">%s</p>', cap)
     img = sprintf(
-      '<img src="%s" alt="%s" %s />',
-      paste0(opts_knit$get('base.url'), .upload.url(x)), alt, .img.attr(w, h, s)
+      '<img src="%s" alt="%s" %s %s />',
+      paste0(opts_knit$get('base.url'), .upload.url(x)), alt, .img.attr(w, h, s),
+      .img.id(options)
     )
     img = add_link(img)
     # whether to place figure caption at the top or bottom of a figure