Change cover art and last.fm

[Exrace]

Is there a config setting that allows a change the provider of album art and show the image dimensions?
Last.fm does work well but I miss the dimensions that use to show when picking art.
Just displaying the size for last.FM will allow you make a informed decision of the art so you don't chose undersized cover art files.

As a feature:
Would be great to have a way to select the provider that you use as default or add additional providers to pick the search provider when you are changing cover art.