June 17th 2014:
Today Spotify released a new Web API.
It is now easy to retrieve cover artwork, as all endpoints includes an array of images for every item.
Search example:
curl -X GET "https://api.spotify.com/v1/search?q=tania%20bowra&type=artist"
{
"artists" : {
...
"items" : [ {
...
"images" : [ {
"height" : 640,
"url" : "https://d3rt1990lpmkn.cloudfront.net/original/f2798ddab0c7b76dc2d270b65c4f67ddef7f6718",
"width" : 640
}, {
"height" : 300,
"url" : "https://d3rt1990lpmkn.cloudfront.net/original/b414091165ea0f4172089c2fc67bb35aa37cfc55",
"width" : 300
}, {
"height" : 64,
"url" : "https://d3rt1990lpmkn.cloudfront.net/original/8522fc78be4bf4e83fea8e67bb742e7d3dfe21b4",
"width" : 64
...
} ],
...
}
}
Old Answer:
You can get the URL to the cover art by calling Spotify’s oEmbed service:
https://embed.spotify.com/oembed/?url=spotify:track:6bc5scNUVa3h76T9nvpGIH
https://embed.spotify.com/oembed/?url=spotify:album:5NCz8TTIiax2h1XTnImAQ2
https://embed.spotify.com/oembed/?url=spotify:artist:7ae4vgLLhir2MCjyhgbGOQ
With JSONP:
https://embed.spotify.com/oembed/?url=spotify:artist:7ae4vgLLhir2MCjyhgbGOQ&callback=callme
http://open.spotify.com/ urls work as well:
https://embed.spotify.com/oembed/?url=http://open.spotify.com/track/6bc5scNUVa3h76T9nvpGIH
{
"provider_url": "https:\/\/www.spotify.com",
"version": "1.0",
"thumbnail_width": 300,
"height": 380,
"thumbnail_height": 300,
"title": "Gusgus - Within You",
"width": 300,
"thumbnail_url": "https:\/\/d3rt1990lpmkn.cloudfront.net\/cover\/f15552e72e1fcf02484d94553a7e7cd98049361a",
"provider_name": "Spotify",
"type": "rich",
"html": "<iframe src=\"https:\/\/embed.spotify.com\/?uri=spotify:track:6bc5scNUVa3h76T9nvpGIH\" width=\"300\" height=\"380\" frameborder=\"0\" allowtransparency=\"true\"><\/iframe>"
}
Notice the thumbnail_url:
https://d3rt1990lpmkn.cloudfront.net/cover/f15552e72e1fcf02484d94553a7e7cd98049361a
/cover/ represents the size of the thumbnail.
Available sizes: 60, 85, 120, 140, 160, 165, 230, 300, 320, and 640.
eg: https://d3rt1990lpmkn.cloudfront.net/640/f15552e72e1fcf02484d94553a7e7cd98049361a