The recommended image sizes for Rara Academic Pro are

Banner: 1349 x 506 pixels

Blog: 358 x 277 pixels

Course: 320 x 231 pixels

Welcome: 520 x 330 pixels

Team: 330 x 358 pixels

Home-team: 584 x 580 pixels

Events 553 x 329 pixels

Home-events: 165 x 182 pixels

Services: 130 x 130 pixels

Testimonial: 134 x 136 pixels

Popular-post: 85 x 70 pixels

Page with sidebar: 730 x 330 pixels

Page without sidebar: 1140 x 430 pixels

Layout post: 246 x 246 pixels

Featured-post: 275 x 275 pixels