Drawing basics: annotation that stays readable

Annotate on a separate layer, always

Before drawing anything on a photograph or screenshot, add a new layer. Your marks then live above the image rather than in it, and you can move, fade, hide or delete them without having destroyed anything underneath.

This costs nothing and saves a great deal. The commonest frustration in image editing is discovering, twenty strokes later, that an arrow is in the wrong place and undo no longer reaches back that far. On a separate layer, you simply clear the layer.

When you are satisfied, flatten before exporting, or just export directly — the editor composites visible layers automatically.

1. Open your screenshot.
2. Choose Add layer in the layers panel.
3. Draw your annotations on the new layer.
4. Adjust the layer’s opacity if the marks overwhelm the image.
5. Export as PNG.

Size your brush to the image, not to the screen

Brush size is measured in image pixels, not screen pixels. A 12-pixel brush on a 4000-pixel-wide photograph is a hairline; the same brush on a 600-pixel screenshot is a thick marker.

A reliable starting point is roughly one two-hundredth of the image width: about 20 pixels on a 4000-pixel image, about 3 on a 600-pixel one. Adjust from there.

If you zoom in to work on detail, remember the brush has not changed size relative to the image, only relative to what you see. This is the correct behaviour, and it is why strokes stay consistent when you zoom back out.

Choose a colour that survives the background

The classic annotation failure is a red arrow on a dark red error message. Before choosing a colour, look at what sits underneath it.

Pure saturated red is a poor default: it is the hardest colour for red-green colour-blind viewers to distinguish, and it vanishes against warm backgrounds. Bright cyan, magenta and yellow-green are rare in photographs and screenshots, so they read clearly against almost anything.

If your mark must cross both light and dark areas, draw it twice: a thicker stroke in a contrasting colour first, then a thinner stroke on top. The result reads as an outlined line and stays visible everywhere.

Shapes beat freehand for anything precise

A hand-drawn rectangle around a button looks hurried; a drawn rectangle looks deliberate. Use the rectangle and ellipse tools for anything you are pointing at, and keep the brush for genuine sketching.

Hold Shift while dragging to constrain a rectangle to a square or an ellipse to a circle. The square follows whichever direction you dragged furthest, so you can build it in any direction from your starting point.

Outlined shapes are usually better than filled ones for annotation, because a fill hides the thing you are drawing attention to. Switch on Fill shapes only when you actually want to mask something.

Redaction is not the same as covering something up

If you are hiding sensitive information, draw a SOLID filled rectangle over it and then flatten the image before exporting. A filled shape on a flattened, re-encoded image genuinely destroys the pixels underneath.

Do not rely on a semi-transparent shape, a blur, or a mark on a hidden layer. Reducing opacity leaves the original values mathematically recoverable, and a hidden layer still contains the data until the image is flattened.

Export to PNG or JPEG rather than sharing a project file, and check the exported image before sending it. This tool never uploads anything, but once you share a file its contents are out of your hands.

1. Add a layer and draw a solid filled rectangle over the sensitive area.
2. Set the layer opacity to 100% and confirm nothing shows through.
3. Choose Flatten in the layers panel.
4. Export, then open the exported file and confirm the area is genuinely blank.

Text that stays readable

Type your text into the toolbar, choose a size, then tap the canvas where you want it to sit. The tap point is the vertical centre of the text, which makes it easier to align with something.

Size text relative to the image for the same reason as brushes. On a wide screenshot, anything below about 2% of the image width becomes unreadable once the image is scaled down in a chat window or a document.

Only system fonts are offered. That is a privacy decision: fetching a font list from a third-party service would send a request every time the text tool opened, which is exactly the kind of quiet leak this tool exists to avoid.

Crop last, export deliberately

Crop after annotating rather than before. Cropping discards pixels permanently, and it is common to discover you needed slightly more context than you thought.

Choose the format for the job: PNG for screenshots and anything with text or sharp edges, JPEG or WebP for photographs. Saving a screenshot as JPEG produces visible smearing around text, which is the single most common avoidable quality loss in shared images.

Questions

Limitations

• Strokes are rasterised immediately: there are no editable vector objects to reposition afterwards.
• Text becomes pixels once placed and cannot be re-edited.
• There is no move or transform tool for selections; a layer cannot be nudged after drawing.
• System fonts only, because no webfont is ever fetched.
• No blur, pixelate or other filter effects, so redaction must be done with a solid filled shape.