What do you call the gesture whereby you rest your palms on the side of your hips?

Arms "akimbo" is a term I have heard used referring to two hands on the waist.

From dictionary.com:

adjective, adverb

with hand on hip and elbow bent outward

It's called.... "putting your hands on your hips", or possibly the "hands-on-hips pose".

Google gives me 1.9m hits for "hands on hips".

Notes on the google result:

• I've used quote marks, to ensure that the three words appeared in that order with no intervening words
• This shows that the three words occur in sequence very frequently. This suggests (although unfortunately doesn't prove) that there isn't a widely accepted single word or simpler phrase
• Compare for example, a description of a salute, which could be "hand at head", "hand by head" or "hand beside head" giving 61000, 19000 and 159 results respectively. These phrases aren't common, because the word "salute" exists and gets used instead.
• Because "hands on hips" is simply describing what is being done, rather than being a set phrase, normal resources like dictionaries don't have it as an entry, so these can't be used as evidence to support this answer. I've checked Cambridge and Merriam-Webster.

In cricket, if a player stands in this pose (with both hands on hips, like the OP's male example) looking angry or frustrated (because another player has messed up, for example) it's often called a "teapot," from the similar shape of an old fashioned teapot with two handles.

Stuart Clark's teapot would have made Glenn McGrath proud

I don't know if that usage has spread elsewhere, though!

The one with both hands on the hips is sometimes called the "Wonder Woman (power) pose", especially in the context of the (now discredited) theory of power posing:

This one has been dubbed the "Wonder Woman" by the media.
_{Amy Cuddy atTEDGlobal 2012: Your body language may shape who you are}

That's right, there's a new power pose in town, and it's called the Wonder Woman: hands on hips, feet wide apart, shoulders back, staring confidently forward.
_{How The Wonder Woman Power Pose Might Actually Help You Get Ahead At Work}

Out of desperation, I tried a little experiment: I struck a Wonder Woman-style pose in the middle of the course in a last-ditch effort to perk myself up, mentally and physically.
_{I Tried "Power Posing" for One Month to See If It Actually Works}

Many of us have turned to the “Wonder Woman” pose during times of stress and anxiety in an effort to exude confidence.
_{'Wonder Woman' Power Pose Does Not Boost Confidence, Testosterone Levels: 3 Hacks To Appear More Confident}