Three transparent media having refractive indices μ_1 , μ_2 , and...

When light rays from the object $O$ fall on the spherical surface, they are refracted by two different media on the right side.

For the upper half of the spherical surface, the light travels from the medium of refractive index $\mu_2$ to the medium of refractive index $\mu_3$. The refraction formula is given by:
$\dfrac{\mu_3}{v_{upper}} - \dfrac{\mu_2}{u} = \dfrac{\mu_3 - \mu_2}{R}$
This is identical to the case where the entire right medium has a refractive index $\mu_3$. Thus, the rays passing through the upper half will form an image at $O''$.

For the lower half of the spherical surface, the light travels from the medium of refractive index $\mu_2$ to the medium of refractive index $\mu_1$. The refraction formula is given by:
$\dfrac{\mu_1}{v_{lower}} - \dfrac{\mu_2}{u} = \dfrac{\mu_1 - \mu_2}{R}$
This is identical to the case where the entire right medium has a refractive index $\mu_1$. Thus, the rays passing through the lower half will form an image at $O'$.

Since the upper and lower halves of the spherical surface act independently and form images at different locations, two distinct images will be formed, one at $O'$ and the other at $O''$.