Using an Online Tool: I Love PDF 3 Tools
Visit ILovePDF3:

Open your web browser and go to Ilovepdf 3.
Upload Your Image:

On the Ilovepdf3 website, click on the Choose file button to upload the image you want to invert.
You can also drag and drop the image file into the designated area.
Invert the Image:

Once your image is uploaded, you should see an Invert button.
Click on this button, and Ilovepdf3 tools will invert the colors of your image.

Download the Inverted Image:

After the inversion process is complete, you will see a preview of the inverted image.
Click on the Download button to save the inverted image to your computer.