After taking a screenshot in macOS, I bring up the markup dialog (introduced in macOS Mojave) and try to use the highlighter tool, but it seems to do nothing. Am I just using it wrong? I'd like to add yellow highlighter to some text in my screenshot.

Steps to reproduce

  1. Initiate a screenshot with ⌘ Cmd - ⇧ Shift - 5
  2. Ensure that Options -> Show Floating Thumbnail is enabled
  3. Capture a still image
  4. Double-click the thumbnail that appears in the bottom right corner. This reveals the markup dialog.
  5. Press the Highlight Selection pen tool

highlight selection tool in markup dialog

Expected Result

Dragging my cursor across the image should highlight white areas in yellow

Actual Result

Dragging my cursor across the image moves the entire window without changing the image content

  • Have you tried using preview and exporting image as a pdf. then try using the highlighter on the PDF file.
    – Natsfan
    Commented Apr 8, 2020 at 23:26
  • 3
    @jmh I don't want to use Preview; I want to use the highlighter on this screen. It's there, so either it's broken or I should be able to use it.
    – Nic
    Commented Apr 9, 2020 at 1:17
  • my comment was saying that maybe the highlighter only works on PDFs. Screenshots are probably jpegs or png and highlighter may not work on an image file.
    – Natsfan
    Commented Apr 9, 2020 at 2:38
  • 2
    Agree with @Nic. If there's a button - it should work or be explicitly disabled (maybe colored grey or smth, idk) Commented Feb 7, 2021 at 20:44
  • 4
    Apparently the highlighter function is for PDFs only, according to discussions.apple.com. It's poor UX. Most people will read the tooltip and waste time looking for a way to create a selection for the highlight button to fill. But there's no way to create a selection on the image. They need to clarify that the button is unusable for images, or (even better) make it work with images, since even the most basic 3rd party screenshot annotation tools have support for highlighting, which is why so many people expect it to work in the first place.
    – Mike Clark
    Commented Apr 20, 2021 at 17:51

1 Answer 1


I found a workaround (needless to say, there shouldn't need to be a workaround).

If you have a device running iOS (or iPadOS) you can hand-off the screenshot to that device.

hand-off to iOS or iPadOS

Once it's been handed off, there you can highlight with a marker. After you are finished editing there, you can tap 'done' and it will bring the edited image back to your computer.

editing screenshot on iOS

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