Build a Modern Desktop Screenshot & Annotation Tool - Day 2: Screenshot Annotator

Projects in this week’s series:

This week, we progressively build a modern desktop screenshot and annotation tool with Python.

• Day 1: Screenshot Capture Tool

• Day 2: Screenshot Annotator (Today)

• Day 3: Screenshot Share Tool

View All Projects This Week

Today’s Project

Yesterday we built a screenshot capture tool. Today we’re adding annotation capabilities — open screenshots, draw arrows and shapes, add text labels, highlight important areas, blur sensitive information, and save annotated versions!

We’re transforming simple screenshots into professional annotated images.

Project Task

Create a screenshot annotator that:

• Opens captured screenshots from your Screenshots folder

• Draws arrows to point at important elements

• Draws rectangles and circles for emphasis

• Adds text labels and annotations

• Highlights areas with semi-transparent overlays

• Blurs/pixelates sensitive information (passwords, emails, etc.)

• Adjusts annotation colors and thickness

• Undo/redo functionality

• Saves annotated versions with “_annotated” suffix

• Clean drawing interface with tool palette

This project gives you hands-on practice with canvas drawing, image manipulation, layering graphics, event handling, and building interactive editing tools — essential skills for any image editing or design application!

Expected Output

Here is how the desktop app looks like. In the example below I have uploaded a screenshot to the app. Then, I drew a rectangle there, some red arrows of different thickness and I even blurred some text on the left side of the screenshot.

Once the user is done with annotating the screenshot, they can press the “Save Annotated“ button to save the annotated image:

That’s an app that comes handy often!

Coming Tomorrow

Tomorrow we’re building a Screenshot Sharing Tool — it shows all screenshots in your screenshot folder and lets you generate a public URL for sharing a screenshot - very handy to share something quick with others.

View Code Evolution

Reveal the working code that produces this exact project using the button below. You will also be able to compare the code with the earlier versions and see how we evolved from simple capture to full annotation capabilities.