Podcast help

Please help! I have been trying to change the cover art for my podcast for months and it still hasn't worked. The art is changed on my website but it hasn't changed on Apple podcast. When I reached out to the Apple people they said I needed to change the image dimensions (which I did) and also to change the name (which I did). I made sure the dimensions were correct, changed the name of the image on my computer and then uploaded the new image with the new downloaded name from my computer onto the podcast page. But like I said the image is updated on my site but not on Apple. Someone else that I spoke to said I need to change the name of the image in the html code but I have no access to that on squarespace or have no idea how to access it. Please help.