How do I add the artist cover on iTunes?

For example I have bone thugs n harmony as one of my artists for my music and I have the albums I want and the album covers but when I look at the artist the artist cover isn't there it's just blank and when I go to my music on my iPhone and click on artists it doesn't show the artist cover but of course when I click on the artist it shows the albums and the album cover. I just hate my artist tab being blank it annoys me all my other artists I have have their picture but not this one so if anyone knows how to fix this please help. I'm running iTunes 12.6.2.20

Whwhw

Find a copy of the artwork elsewhere on the Web. Copy it to your desktop. Right-click on the file(s) and select Get Info. Select the Artwork tab. You'll get a blankish box. Press Add Artwork, and then insert the filename of the cover tile. Then press OK.