Image sizes
Besides the default formats (thumbnail, medium, large, full) with Mood you can resize images on fly as you prefer, as you can see here below
medium (default ratio)
600×600 (ratio 1:1)
600×450 (ratio 4:3)
600×338 (ratio 16:9)
Galleries
Here below are simple galleries created by using the WordPress native gallery shortcode, though the UI available from the text editor.
Advanced galleries
Mood also provides a Visual Composer module to create advanced galleries easier to manipulate: you can decide border radius, effects, links and also filters.