As the person above me said, standing sprites can be in 3 different sizes. Each standing sprite has 3 poses of animation that animate in a 1-2-3-2-1 pattern. This is what’s used to give them that lively bobbing up and down they do on the map.
Each map sprite also has a moving or active version. These sprites are always 32x32.
When a unit is selected, they have 3 poses that animate in the same pattern. Usually, this will be a more actionable pose than the standing one - bucking on a mount and lifting up a weapon are the most common ones. This animation is also used when using a staff or item on the map, so for staff users this will always involve lifting up their staves in a casting motion.
Each unit also has 3 walking animations of 4 frames each - up, down, and to the left (right movement just mirrors the left walking sprites). These animate in a different loop of 1-2-3-4-1-2-3-4-… instead so the final frame needs to loop into the first.
Each sprite uses a 16 color palette (as most things in GBA do). Every faction has their own 16 color palette that all sprites of that faction use.
From top to bottom you have - Player, Enemy, NPC, Gray (only used in the link arena), and grayed out (when the unit has already moved or is petrified).
The graphics are the same but loaded using the associated faction palette.