If you're in the market for a tool to create cover art for your podcast, Daft Art is a great option. This AI album cover generator produces results that look like they were created by a human designer, with features like curated styles, an easy-to-use editor and high-resolution output (3000x3000px). You can customize font styles, colors and other elements, and you retain full rights to the images you create. Daft Art offers two subscription tiers at reasonable prices, so it's a good option for podcasters.
For a general-purpose image generation tool, Artsmart.ai could be useful. Although it's geared more for generating images from text prompts, it also offers tools for upscaling, inpainting and background removal. That could be useful if you want to create a sequence of images for your podcast, and the service offers a range of pricing tiers depending on your needs.