This is called relief inversion.

The two pictures are exactly the same, just rotated upside down.

Most people have a subconscious interpretation of images based on the assumption that objects are illuminated from above. We expect the light source to come from the upper left corner of an image and when it doesn’t our brains flip reliefs into carvings and vice versa to compensate.

This happens on geographical maps as well,

Essentially, our brain interprets shadows as indicators of depth, considering them to be depressions or valleys. When shadows appear on the northern side of features due to a southern light source (or vice versa in the Southern Hemisphere), our brain reads this correctly.

However, when the light source is from the north (or the south in the Southern Hemisphere), shadows appear on the southern side of features, causing our brain to misinterpret these shadows, seeing elevated areas as depressions and depressed areas as elevations.