Image Annotation Tool
Add text, rectangles, and arrows to an image
Click to add text. Drag to draw rectangles or arrows.
Image Annotation Tool — what it does
Mark up an image directly in the browser: click to place text labels, drag to draw rectangles or arrows, choose the colour and line width, undo the last mark or clear everything, then download the annotated PNG. It covers what most screenshot annotation actually needs — point at the thing, box the thing, name the thing.
When this tool helps
- Marking up a screenshot to show a developer exactly which element is wrong.
- Highlighting a clause or figure in a scanned document before sending it on.
- Numbering steps on a product photo or interface capture for a how-to guide.
How to use it
- Choose the image to annotate.
- Pick a mode: text, rectangle or arrow, and set colour and line width.
- Click to place text, or drag to draw shapes.
- Undo or clear if needed, then download the PNG.
Accuracy, limits, and good practice
- Pick a colour that does not appear in the screenshot — magenta and bright red survive most interfaces, while grey and blue vanish into them.
- Fewer, larger marks communicate faster than many small ones; three arrows on one image is usually the limit before it turns into noise.
- Annotations are burned into the exported image and cannot be edited afterwards, so keep the clean original if you may need to revise.
Frequently asked questions
Can I edit an annotation after placing it?
Undo removes the most recent mark, and clear resets everything; individual marks cannot be selected and moved.
Why is the exported file a PNG?
PNG keeps text and lines crisp. JPEG compression would blur the sharp edges of arrows and labels.
Is my image uploaded?
No. Everything is drawn on a canvas in your browser and the export never leaves the machine.
Related tools on this site
- Circular Avatar Crop — Crop an image into a circular PNG avatar
- Image Color Replacer — Replace a selected color using adjustable tolerance
- Pixelate & Blur Image — Apply privacy-friendly pixelation or blur and download the result
Everything above runs inside this page. Image Annotation Tool needs no account, no upload, and no server round trip — close the tab and nothing is left behind.
圖片標註工具能做什麼
直接在瀏覽器中為圖片加註：點擊放置文字標籤、拖曳畫出矩形或箭頭，可選顏色與線寬，能復原最後一筆或全部清除，最後下載加註後的 PNG。它涵蓋了截圖標註真正需要的動作——指出來、框起來、寫上名字。
什麼時候用得上
- 在截圖上標註，讓工程師一眼看到是哪個元素出問題。
- 在掃描文件上圈出條款或數字，再轉寄出去。
- 為操作教學在產品照或介面截圖上標示步驟編號。
使用步驟
- 選擇要標註的圖片。
- 挑選模式：文字、矩形或箭頭，並設定顏色與線寬。
- 點擊放置文字，或拖曳畫出圖形。
- 視需要復原或清除，最後下載 PNG。
精確度、限制與實務建議
- 選一個截圖裡沒有的顏色——洋紅與亮紅在多數介面都跳得出來，灰與藍則會被吃掉。
- 少而大的標記比多而小的更好懂；同一張圖三個箭頭大致就是變成雜訊前的上限。
- 標註會燒進匯出的圖片、事後無法編輯，可能還要改就請保留乾淨原檔。
常見問題
放好的標註可以再修改嗎？
復原可移除最後一筆，清除會全部重來；個別標記無法選取搬移。
為什麼匯出成 PNG？
PNG 能讓文字與線條保持銳利，JPEG 壓縮會讓箭頭與標籤的邊緣糊掉。
圖片會被上傳嗎？
不會。所有繪製都在瀏覽器的 canvas 上完成，匯出檔也不會離開這台電腦。
本站相關工具
以上步驟全部在這個頁面內完成，圖片標註工具 不需要註冊、不上傳檔案、也不經過伺服器，關閉分頁後不會留下任何資料。