Sometimes I have inappropriate and nude images of girl in my gallery as well as Quranic quotes. When I open gallery it appears together. Is this a sin . Note - I have deleted these inappropriate pictures

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu ʻalayhi wa sallam, is His Slave and Messenger.

Firstly, it should be noted that keeping these images on the phone is a sinful act in and of itself and the doer bears a sin for that. The prohibition in this regard is more emphasized and the sin is graver when these images are saved along with those featuring the verses of Quran; such an act constitutes disrespect for the Quran and it is incumbent to honor the Quran and keep it protected from such disrespect.

If you had nothing to do with keeping these images or saving them along with the verses of the Quran, you bear no sin for that. Rather, the one who did so bears the sin as highlighted above.
You shall earn the rewards for erasing such prohibited images, Allah willing.

If you were the one who saved these images on the phone along with those featuring the verses of the Quran, it is incumbent on you to repent to Allah of such a sin. Please, refer to Fatwa 86527 about the conditions of the repentance.

Allah knows best.