compare O2 O3 bond strength ?

The bond in a O2 molecule is a double bond and no delocalization of electrons there.

However, With reference to the suggested structure of O3:

O = O → O where → is a datave bond.

Owing to resonance effect, the pi-electrons of the double bond are delocalized and hence both bonds in the molecule are the intermediate between single and double bond.

Thus, bond strength of O3 is weaker than O2.