Waifu Deck

Waifu Deck is a free, open source Android app for browsing and collecting anime illustrations. Images come from ten image sites, including Danbooru, yande.re, Konachan and waifu.im, and appear one at a time as a card deck. Swipe left to skip and right to save, and undo a swipe if you change your mind.

Saved images are kept at their original size on your phone, and the album works offline. You can filter by SFW or NSFW and by source, and sort by save time, resolution or file size. Optional sync uses your own cloud storage, such as Cloudflare R2 or Google Drive, and files are encrypted on your device before upload.

No account or sign-up is needed, and there are no ads or analytics. The code is public under AGPL-3.0 on GitHub, so you can review how it handles your images and keys. It suits anime fans who want a private personal library on their own phone.