What others have said. For JPEGs just cut out the background, create a layer behind it with the colour or texture of your website and save in the format of your choice.

Open the Paint application and import the image you want to edit. In the Microsoft Paint app on Windows 11, with an image loaded, find the "Remove Background" option in the Command bar.

(According to this week’s announcement, the background removal feature can now create transparent backgrounds.) Before that, Paint got a top-down visual refresh introducing dark mode support ...