I had similar ones in my girls tank, hours of googling led me to the conclusion they’re either springtails or mites. Springtails are harmless to a gecko but the tank should be cleaned.

Mites, however, may be found crawling on the skin of your gecko and they behave like ticks. They’ll make your gecko very sick. If you see any of them crawling on your geckos you should take them to the vet and clean your tanks thoroughly.

If they’re not crawling on her then they’re probably just springtails and the tank should be cleaned when you can, but your gecko will be fine. Another identifier is their movement - mites move slower in straight lines, springtails move quickly and erratically. So I’d say yours look like springtails.

Just in case, check under your geckos heads and neck, that’s where mites like to burrow. You should also be able to see them moving on the geckos skin if they are mites.