Adding the query string attribute is easy, but pulling a larger thumbnail from Last.fm was originally going to be tricky because the default size for the album images is only 64x64 pixels.

That being said, the images are being served via Akamai.

https://lastfm-img2.akamaized.net/i/u/64s/152aa27fbc342bff7485684425129ff5.webp

The 64s in the URI specifies the one optimized size of the thumbnail. If you change it to anything other than 64s (or leave it out entirely), the original full-size image gets served instead. The sizes for the original images are all over the map, but most seem to be 600x600 pixels or larger.

For example:

https://lastfm-img2.akamaized.net/i/u/s/152aa27fbc342bff7485684425129ff5.webp