Great many of android users don’t know it is possible to directly recover photos from android phones/tablets without backups.
When you delete photos(or other files) on your Android device, it isn't really erased- it continues existing. That's why you can retrieve deleted photos from android without needing of backup. Deleting a file's pointer and marking its space as available is an extremely fast operation. In contrast, actually erasing a file by overwriting its data takes significantly longer. For example, if you're deleting a 1 GB file, that would be near-instantaneous. To actually erase the file's contents, it may take several minutes – just as long as if you were writing 1 gigabytes of data to your Android device. In that case, once you accidentally lost photos, messages, videos, and other documents from your device, don’t use your device immediately, so that the deleted data won’t be overwritten.
Though, the lost data still exist, you have to get help from 3-rd party android recovery tool to get them back. Commonly, you can search android phone recovery, the result on the first page may meet your demand. Some android photo recovery guides on Youtube are good. You’d better do some researches on your side to choose a android data recovery software in four factors: supported android models, supported file types, scan speed, scan result.
This is a review of android data recovery:
Android Data Recovery Review: Jihosoft Android Phone Recovery VS Wondershare Dr.Fone for Android | Samsung Galaxy Recovery
From my own experience, Jihosoft android data recovery program is a good choice to do the job. It did work for me and recovered deleted photos from my galaxy s6.