iCloudS3

An S3-compatible object store backed by iCloud Shared Photo Albums. Quota policy: Apple's Shared Album loophole.

Apple gives every iCloud account 5 GB of free storage, then charges monthly for iCloud+. However, Apple's published iCloud Shared Albums policy states that photos and videos in Shared Albums do not count against your iCloud storage.

An Apple ID can create 200 Shared Albums, each holding 5,000 photos up to 2048×2048 pixels. A lossless 2048×2048 24-bit RGB PNG holds 12.18 MB of raw pixel data. That is up to 1,000,000 objects (~12 TB of raw capacity) stored at 0 bytes of iCloud Drive quota.

icloud-s3 is a Rust server that speaks the Amazon S3 XML REST protocol (aws s3, boto3, rclone, s5cmd) and stores every object inside the RGB pixels of lossless PNG carrier images in Shared Albums. Each image has a 64-pixel visual HUD banner burned into the top so your production database backups are readable when you scroll past them in Photos.app.

cargo install --path .
icloud-s3 serve --dry-run                       # in-memory Shared Album, no iCloud needed

Point the unmodified AWS CLI at http://127.0.0.1:9000, or run the built-in Terminal UI benchmark:

export AWS_ACCESS_KEY_ID=icloud
export AWS_SECRET_ACCESS_KEY=shared-album-loophole
export AWS_DEFAULT_REGION=us-east-1

aws --endpoint-url http://127.0.0.1:9000 s3 mb s3://prod-backups
aws --endpoint-url http://127.0.0.1:9000 s3 cp Cargo.toml s3://prod-backups/manifests/Cargo.toml
aws --endpoint-url http://127.0.0.1:9000 s3 ls s3://prod-backups --recursive
aws --endpoint-url http://127.0.0.1:9000 s3 cp s3://prod-backups/manifests/Cargo.toml /tmp/Cargo.toml

# Run the live Terminal UI benchmark (10 photos + 1 ZIP bundle vs Cloudflare R2)
icloud-s3 bench --endpoint http://127.0.0.1:9000 --bucket prod-backups --input-dir demo/sample-photos

Fetch any S3 object with ?format=png (http://127.0.0.1:9000/prod-backups/manifests/Cargo.toml?format=png) or open the Shared Album backing folder in macOS Finder / Photos.app to inspect the 24-bit RGB carrier images.

# Persist every bucket as an album folder of 24-bit RGB PNG frames on disk
icloud-s3 serve --album-dir ./albums-live --shards 4

# Also import each written PNG frame directly into macOS Photos.app via AppleScript
icloud-s3 serve --album-dir ./albums-live --shards 4 --sync-photos-app

You can also encode and decode files directly from the CLI without running the HTTP server:

icloud-s3 encode --input backup.sql --output backup.png --bucket prod-backups --key db/backup.sql
icloud-s3 decode --input backup.png --output restored.sql

Why encode bytes into pixels instead of EXIF or PNG tEXt chunks? Media pipelines strip ancillary metadata chunks on upload. If Apple changes a single pixel value, icloud-s3 catches it immediately via the embedded CRC32 and SHA-256 digests.

Run the built-in 10-case correctness evaluation and throughput benchmark suite:

icloud-s3 eval --json docs/eval-report.json --markdown docs/eval-report.md

icloud-s3 scales writes by sharding keys across multiple Shared Albums (icloud-s3-<bucket>-01 … -08) using CRC32 hash slots:

Measured live against a production Cloudflare R2 bucket (10 test JPEGs + 11-photos-bundle.zip containing all 10 photos and a JSON manifest, verified with shasum -a 256 and unzip -t):

Below is an actual 560×160 lossless 24-bit RGB carrier PNG (demo/sample-carrier.png) generated by icloud-s3 encode --input Cargo.toml --output demo/sample-carrier.png --bucket prod-backups --key manifests/Cargo.toml. You can download this image from GitHub and run icloud-s3 decode -i demo/sample-carrier.png -o Cargo.toml to recover the exact file:

• Buckets (Shared Albums): ListBuckets (GET /), CreateBucket (PUT /:bucket), DeleteBucket (DELETE /:bucket), HeadBucket (HEAD /:bucket)
• Objects (RGB Carrier Frames): PutObject (PUT /:bucket/*key, including AWS SigV4 STREAMING-AWS4-HMAC-SHA256-PAYLOAD chunked uploads), GetObject (GET /:bucket/*key), HeadObject (HEAD /:bucket/*key), DeleteObject (DELETE /:bucket/*key), DeleteObjects (POST /:bucket?delete)
• Listing: ListObjects & ListObjectsV2 (GET /:bucket?list-type=2&prefix=...&delimiter=...&max-keys=...)
• Visual Inspection: icloud-s3 bench (live Terminal UI) and GET /:bucket/*key?format=png (raw 24-bit RGB carrier PNG)

Apple's published Shared Album limits state that Shared Albums do not count against iCloud storage, while enforcing activity and item limits:

• Maximum Shared Albums per owner: 200 albums.
• Maximum photos/videos per Shared Album: 5,000 items.
• Maximum combined hourly / daily contributors & uploads: 1,000 photos per hour and 10,000 photos per day across Shared Albums.
• Resolution limit: Photos in Shared Albums are limited to 2048 pixels on the long edge (up to 5449 pixels for panoramas). icloud-s3 keeps every generated PNG frame at or below 2048×2048 pixels.
• Recompression risk: While PNGs imported locally or kept in album directories remain bit-exact, if Apple's server-side Shared Album pipeline transcodes an asset to lossy JPEG/HEIC on a downstream device, the least-significant bits of the RGB channels will change and icloud-s3 will fail closed with ChecksumMismatch.