Serving Scaled Images…

I'm currently using My Music Band Pro which appears to have set custom sizes (120x120) for SHOP THUMBNAILS and WOOCOMMERCE GALLERY THUMBNAILS. The product table I'm using wants the images at 59x59. For reference: https://gtmetrix.com/reports/showchoircharts.com/zSrv8RSr My original images are 300x300 and I want to keep them that way for the product pages. So my questions: 1. How do I change the theme's default thumbnail sizes? 2. And how do I regenerate the thumbnails after doing so? Page in question: https://showchoircharts.com/catalog/ Thank you, jg