There are 2 repositories under android-gallery-sample topic.
A simple implementation of an image gallery app in android
Open source Image Gallery with tons of feature .
download image from http url and show in recycler grid view, without using any kind of http and imagedownload library.
Gallery view for Image and Video in Android
Android custom GridView gallery with text and image.Material design components are used for nice looking UI
It is an gallery application. It has the features of listing albums, images and allow users to zoom in/zoom out the image.
Tutorial how to open the gallery on your device and choose a photo to use in your app
Android Gallery app