If you’re having a problem getting your podcast image to display properly on iTunes , I found a link to a video tutorial that might be helpful. The video was created in 2012 when the minimum size of an image for your podcast needed to be 600 x 600 pixels. iTunes has now changed the minimum size to 1400 x 1400 — with a maximum size of 3000 x 3000 pixels.
Here is the link to the video that you may find helpful: http://www.incomepress.com/podcast-image-artwork-itunes
And here is the link (which you may already have seen) to iTunes specifications: https://help.apple.com/itc/podcasts_connect/#/itc1723472cb
We’ve used various stock photo websites through the years for images. I like Adobe’s library. It’s not free, but it vast and fairly reasonable.
I hope this helps you prepare your podcast artwork for iTunes. If you need help with the editing and enhancing of your podcast, or you want a cool intro and outro, we hope you’ll check us out at Audiobag.