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  3. Image Annotator
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Image Annotator

Annotate images with arrows, shapes, text, highlights, and blur regions. Perfect for screenshot markup, tutorials, and documentation.

Add arrows, circles, text labels, rectangles, and other annotation shapes on top of images. Built for marking up screenshots, highlighting areas of interest in photos, or creating visual instructions. More structured than freehand drawing, each annotation is a separate, movable object.

Edits stay in your browserMore image processingJump to full guide

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Image Annotator: a worked example

You need to mark up a screenshot with arrows and a callout to explain a bug in a ticket.

Input

bug.png + 2 arrows, a box, "broken here" label
Image Annotator produces

Output

bug_annotated.png with the markup flattened in

Arrows, boxes, and text turn "it looks wrong" into an unambiguous report, which shortens the back-and-forth on a bug. The annotated copy is exported flattened so it renders the same everywhere.

About the Image Annotator

Add arrows, circles, text labels, rectangles, and other annotation shapes on top of images. Built for marking up screenshots, highlighting areas of interest in photos, or creating visual instructions. More structured than freehand drawing, each annotation is a separate, movable object.

How to use

  1. 1Upload the image you want to annotate
  2. 2Select an annotation tool (arrow, circle, rectangle, text, etc.)
  3. 3Click and drag on the image to place annotations
  4. 4Adjust color, size, and position of each annotation
  5. 5Download the annotated image

Where this helps

  • Bug reports

    Mark up screenshots to clearly show where an issue occurs.

  • Tutorial creation

    Add numbered steps and arrows to screenshots for how-to guides.

  • Design feedback

    Annotate mockups with comments and change requests.

  • Documentation

    Create visual instructions by labeling interface elements.

Key features

  • Arrow, line, circle, and rectangle shapes
  • Text labels with font size control
  • Customizable colors and line thickness
  • Movable and resizable annotation objects
  • Numbered markers for step-by-step instructions
  • Export with annotations baked in

Tips & best practices

  • Hold off on downloading until you're done: every arrow, shape, and text box stays an editable object you can re-select, move, or restyle, but the Download PNG step flattens them permanently into the image.
  • Use the Highlight tool (translucent 0.3-opacity fill in the stroke color) to mark areas, and the object-based Eraser to remove a misplaced annotation with a single click without affecting the underlying photo.
  • Zoom in (up to 300%) for precise placement on detailed screenshots; the export still renders at the image's full native resolution thanks to a 1/zoom multiplier, so zooming never softens the result.
  • Learn the single-key shortcuts (R rectangle, C circle, A arrow, L line, P pen, T text, V select, H pan) plus Ctrl+Z / Ctrl+Shift+Z and Ctrl+D to mark up screenshots quickly.

Examples

  • Marking up a screenshot for documentation

    Press A for the Arrow tool and drag from a caption toward a button; the tool draws a line and grouped triangular arrowhead in your stroke color. Switch to Rectangle (R) with no fill to box a region, then press T and click to drop editable IText labels, toggling Bold for emphasis. Download PNG composites everything at full resolution as annotated-<yourfile>.png.

  • Drawing attention with a translucent highlight

    Select the Highlight tool and drag over a paragraph or UI element; it lays down a rectangle filled with the current stroke color at 0.3 opacity so the content beneath stays visible. If you misplace it, switch to the Eraser and click it to remove just that object, then re-select another tool and continue.

How it works

The Image Annotator is built on Fabric.js v6 and treats every mark you add as an independent vector object rather than baking it into the image. Thirteen tools are available: Select, Pan, Arrow, Line, Rectangle, Circle (drawn as a Fabric Ellipse), Triangle, Star, Polygon, Freehand, Text, Highlight, and Eraser. Because each shape stays a live object, you can re-select, drag, resize, rotate, duplicate (Ctrl+D, which offsets the copy by 20px), flip horizontally or vertically, and reorder it with Bring Forward / Send Backward at any time before export. Selecting one or more objects pops up a floating control bar showing the selection count alongside duplicate, flip, layer, and delete buttons. The Eraser tool is object-based, not pixel-based: clicking an annotation removes that whole object (the background image is never touched).

Several tools have specific construction logic worth knowing. The Arrow tool draws a Fabric Line during the drag, then on mouse-up appends a triangular arrowhead Polygon whose length is Math.max(15, strokeWidth * 3) and groups the two into a single movable object. The Star tool generates a five-spike polygon and the Polygon tool generates a six-sided hexagon, both created at a base radius of 50 and scaled during the drag for smooth resizing. The Highlight tool draws a filled rectangle using the current stroke color at 0.3 opacity, so it acts like a translucent marker over the area beneath it. Text is added with Fabric's IText (inline-editable on click) in a system-ui font, with Bold and Italic toggles and a font-size dropdown offering 12, 16, 20, 24, 32, 48, 64, and 96px. Stroke color is chosen from a 10-swatch palette or a react-colorful hex picker, with a separate fill color (defaulting to transparent / 'No Fill') and stroke widths of 1, 2, 4, 6, 8, 12, or 16px.

Editing is non-destructive and reversible. The tool keeps an undo/redo history of up to 50 states, serialized with Fabric's toDatalessJSON, and history is committed only when a draw completes (on mouse-up or path:created) so partial 1x1 shapes are never recorded; Ctrl+Z undoes and Ctrl+Shift+Z redoes. The canvas zooms from 25% to 300% in 25% increments with a reset-to-fit button, and a status bar reports the image's native pixel dimensions, the live object count, and the current zoom. Single-key shortcuts switch tools (V Select, H Pan, R Rectangle, C Circle, L Line, A Arrow, P Pen/Freehand, T Text), and Delete/Backspace removes the selection. Export is a single Download PNG action that composites the original background and every annotation at full native resolution (using a 1/zoom multiplier so on-screen zoom never degrades output) and saves the file as annotated-<original-filename>.png. All processing runs in the browser via canvas; the image is loaded through an object URL and never uploaded.

Frequently asked questions

Can I move annotations after placing them?

Yes. Each annotation is a separate object that can be dragged, resized, and edited after placement.

Is there a limit to the number of annotations?

No practical limit. Add as many as your image needs.

Can I annotate without an uploaded image?

The tool is designed for annotating existing images. For drawing on a blank canvas, use the Drawing Canvas tool.

Related tools and how they differ

  • Image Pixelator: Applies a whole-image mosaic with square, circle, diamond, or hex tiles plus palette reduction for retro art or casual censoring; mosaic is partially reversible, so for true redaction draw a solid filled box instead.
  • Meme Generator: Places draggable Impact-style top and bottom captions with outline and bold styling; use it for shareable meme text, not precise markup objects.
  • Screenshot Beautifier: Adds a colored background, padding, shadow and browser or phone frames around an image; use it for presentation polish, not for arrows or callouts.

Private by design

Images are decoded, edited, and exported entirely inside this browser tab. No originals, exports, or metadata are uploaded.