Online Tool Store
Screenshot Annotation Generator
Annotate a screenshot with arrows, boxes, highlights, numbered steps and text labels, pixelate private details, then export a full-size PNG. No upload.
This works right here on your device — nothing gets sent out.
Example shown — paste, drop, or choose your own screenshot to replace it.
or paste with Ctrl+V. Nothing is uploaded.
How Screenshot Annotation Generator works
- Paste a screenshot with Ctrl+V, drop it on the canvas, or choose the file.
- Pick a tool and a colour: drag to draw arrows, boxes, highlights and redactions; click to place numbered steps and text labels.
- Use Undo, Redo or Clear to fix mistakes — the step counter follows along.
- Download the annotated screenshot as a full-size PNG, or copy it to your clipboard.
How sizes and redaction work
Annotation sizes are tied to the screenshot, not to your screen. One size unit is the screenshot's longest side divided by 1000, so a medium arrow is 4.5 units thick: 4.5px on a 1000px capture and 13.5px on a 3000px one. Redaction shrinks the selected area of the original screenshot into blocks of at least 14 units and scales them back up without smoothing, so only the block colours reach the exported file.
unit = max(width, height) ÷ 1000 · redaction block = max(8px, 14 × unit × size)
FAQ
How do I add arrows and numbered steps to a screenshot?
Paste the screenshot with Ctrl+V (or drop the file), choose Arrow and drag from the start point to what it should point at, then choose Step and click each place in order — the numbers count up automatically. Download the PNG when you are done.
Is pixelating a screenshot safe for hiding passwords or emails?
The exported PNG contains only coarse colour blocks where you redacted, not the original pixels, so the text cannot be read from the file. For very short or predictable values, use the L size so each block covers more of the text, or cover them with a box instead.
Will the exported image lose quality?
No. Annotations are drawn onto your screenshot at its original pixel size, up to 8192 pixels on the longest side, and saved as a lossless PNG. Arrow, label and step sizes scale with the image, so they look the same on a retina capture.
Can I undo or remove an annotation?
Yes. Undo removes the last annotation and Redo brings it back; Ctrl+Z and Ctrl+Shift+Z (Cmd on Mac) work too. Clear removes everything, and Redo can restore it. Annotations cannot be moved after they are placed — undo and draw again.
Can I copy the annotated screenshot straight into Slack, Jira or a document?
Yes. Copy image puts the finished PNG on your clipboard, so you can paste it directly into chat, a ticket or a doc. If your browser blocks image copying, use Download PNG.
Is my screenshot uploaded?
No. The screenshot and every annotation are drawn on a canvas in this browser tab, and the PNG is created on your device.
How we compare
| Feature | Online Tool Store | Supademo Annotation Generator | SOPX Image Annotate |
|---|---|---|---|
| Arrows, boxes, highlights, numbered steps, text and redaction | Yes | Yes, plus AI auto-placement | Yes, plus ellipses, freehand and emoji |
| Screenshot processed in your browser | Yes | Not stated on its page | Yes |
| Full resolution for large screenshots | Up to 8192px | Not stated on its page | Downscales above 4096px |
| No account and no watermark | Yes | Yes | Yes |
If you want to mark up a screenshot quickly — arrows, steps, labels and redaction — and keep it private and full-size, Screenshot Annotation Generator does it right in this tab.