Missing taken pictures on the offline Iphone and not sync with Icloud

I was taking pictures offline yesterday and running low storage space but my iphone was not sync with Iclowd by the mobile carrier. now I see a lot of taken pictures are missing from my iphone. Did I lost my pictures or I can recover them?

I took the pictures while I was walking by street but I didn't have mobile service because I am in other country. I knew my iphone was running low storage space but I remember to see the missing pictures before the night, today one day after I noticed a lot of missing pictures.

my question is.

are the pictures deleted by the iphone and I can't recover them?

or I can recover them because they are hidden in some place inside the iphone?

I never receive the alert while I was walking?

I free uup some space the day before but any way the pictures get disappeared.

thank you in advance

any help will be appreciated.

Robert