1a. Click on the Start Menu, navigate to the Windows Accessories folder and click on it, then click on Paint.
1b. You can also click on the Start Menu and start typing "Paint", then click on any of the search results highlighted to open the app.
2. Open your image by dragging it into Paint, or by clicking on File in the top-left corner, then Open, and then choosing your image.
3. Once your image is loaded, click the Resize button on the Home tab.
4. Adjust the size of your image according to your needs - a vertical size of about 60 pixels is optimal for most logos. Make sure "Maintain aspect ratio" is checked to avoid distorting your image when resizing. Click OK when you're done.
5. Your image will be resized. If you are not satisfied with the result you can click the blue left arrow in the top-left corner or hit Ctrl+Z to undo and restart the process.
6. Click on "File" in the top-left corner, then "Save as", and finally choose your image type. Logos are best saved as PNG, while announcements and pictures are best saved as JPEG. Choose your file destination and click OK.