Apps for jpeg format flashcards

[meflower]

I am wondering what apps you used for viewing flashcards in jpeg format on phones or pads.

I was putting all jpeg files of one section into one camera roll. Then I have to go through the whole section each time.

Ideally, one app could allow me to make two folders, done or to-be-reviewed. Thus I can move cards from to-be-reviewed gradually to the "done" folder. Each time I only go through the to-be-reviewed folder.

Thanks for sharing your experience!