Please make sure to use the images of the following sizes (in px).
App Landing Page Banner: 1366 x 750
App Landing Page Featured: 170 x 170
App Landing Page With Sidebar: 750 x 340
App Landing Page Without Sidebar: 1140 x 437
App Landing Page Features: 110 x 110
App Landing Page Video Image: 795 x 450
App Landing Page Featured Post: 170 x 170
App Landing Page Recent Post: 78 x 58