Some people like to add cover art to there podfics. These are typically square images reminiscent of old CD covers. This step is entirely optional. It is completely valid to post your work without cover art. You could also post it using the "Cover Art Welcome" tag on AO3 and someone else might just come along and make some cover art for you.
A Dreamwidth index post rounding up many free sources for fonts images, and videos.
Making great cover art doesn't mean having to pay for expensive software subscriptions. Check out the free programs below.
The website below are libraries of free to use images that you may include in your cover art. The licenses may vary though, so please check the attributions requirements before use.
To post cover art on AO3, first you need to post it to a different website that will host the image for you. Explore the links below to find the image hosting website and method that is right for you, or click the image hosting tips link for more ways to host your images.
Podfic cover art is a beautifully diverse thing wherein there are no rules. The image generators below may also be helpful in creating your own works.
A GIMP plugin to remove the background of an image with remove.bg API, while keeping the original image size.
Image sets modeled on the Penguin Classics line of books