Stackd vs Flattr
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Stackd
Easily share and save multiple photos with friends and family. Upload images to create a shareable stack, and recipients can swipe right to save or left to discard. Saved images are then downloaded to their device.
- Bulk image sharing
- Swipe to save/discard
- Download saved images
- Create image stacks
- Stacks expire after 2 days
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With Stackd, you can seamlessly share and save images in bulk with your friends and family. Share a Stack and get swiping! - Once you receive your Stack, swipe right on the images you want to save, swipe left on the images you want to discard - At the end of the Stack, simply download the saved images to your device - Create a Stack by uploading images in bulk to share with your friends - You will have 2 days to swipe through your Stack before it expires You can view our End User License Agreement here: https://www.stackdsocial.com/eula
Flattr
Create perfectly balanced photos by merging multiple exposures using advanced GPU exposure fusion. This app allows photographers to stack, overlay, and combine bracketed shots for natural-looking results without filters or subscriptions. Export in TIFF or JPEG formats.
- Real exposure fusion, not filters
- Supports RAW (.DNG) and JPEG inputs
- TIFF and JPEG export
- GPU-accelerated processing
- Auto image alignment
- Photo stacking and blending
- Double exposure and overlay effects
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Merge multiple exposures into one perfectly balanced photo — real GPU exposure fusion. Free, no subscription required. Flattr is built for photographers who use exposure bracketing and want clean, natural results. Stack shots, overlay frames, combine exposures — export TIFF or JPEG. No account, no hidden fees. — WHY FLATTR — Most photo apps fake results with tone-curve filters. Flattr does real exposure fusion: it computes weight maps per pixel across contrast, saturation, and edge detail, then blends your exposures through a Laplacian pyramid. The result looks like your eyes saw the scene — not like a preset applied in batch. • Real exposure merge — not a filter • Supports RAW (.DNG) and JPEG inputs • TIFF export • GPU-accelerated — fast even on large files • Auto image alignment via Vision framework • No account, no subscription, no hidden fees — WHAT YOU CAN DO — Photo Merge & Photo Stacking: combine two or more exposures from any exposure bracketing sequence into one seamless image. Flattr aligns your shots automatically before blending, so handheld bracketing works too. Stack three, four, or five photos and get a single frame where every zone is properly exposed — highlights controlled, shadows open. Exposure Blending: weight each pixel by how well-exposed it is. The classic exposure stacking result — without Photoshop, without a desktop. Combine photos straight from your camera roll or imported DNG files. Double Exposure: overlay two photos for artistic compositions. Superimpose a portrait over a landscape, blend a city skyline into a forest, or combine photos into something entirely new. Blend modes give you full control over how the images interact. Overlay & Superimpose: layer photos on top of each other with precise control. Great for creative composites, architectural photography, and experimental work. Superimpose any two images and export at full resolution. Exposure Fusion: balanced light from bracketed shots, without an over-saturated look. Flat, natural, and true to the scene. This is what your eyes see when standing in a bright landscape — Flattr captures it the way your camera can't do alone. — HOW IT WORKS — 1. Select your bracketed exposures from your photo library or import DNG/RAW files directly 2. Reorder if needed — drag to set the blend sequence 3. Tap Merge — Flattr aligns, weights, and fuses in seconds 4. Export as TIFF (full RAW workflow) or high-quality JPEG — WHO IT'S FOR — Landscape and travel photographers who use exposure bracketing to handle tricky light. Architectural photographers dealing with bright windows and dark interiors. Night photographers blending a sharp foreground with a sky. Street photographers layering multiple frames for creative effect. Anyone who wants to combine photos, superimpose images, or fuse exposures and keep every detail. — EXPORT — RAW workflow: exports full-quality TIFF. Compatible with Lightroom, Darkroom, and any TIFF-capable raw editor. JPEG workflow: exports high-quality JPEG optimised for sharing and social. — TECHNICAL — Built on Metal GPU processing and Apple's Vision framework for image alignment. Laplacian pyramid blending preserves fine texture and edge detail that simple opacity-based layer blending destroys. Works on iPhone and iPad. Supports DNG, RAW, and JPEG inputs. Flattr. Real photo blending, made simple. Download free and merge your first bracket in under a minute.
Screenshots
Verdict
The clearest difference is update cadence: Stackd at every 4 days against Flattr's every 10 days. Stackd also leads on iOS requirement (15.1 vs 17.6). On price, ads, in-app purchases and monetization model there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Stackd ships an update every 4 days, Flattr every 10 days. The most recent releases landed on September 29, 2026 and October 7, 2026 respectively.
| Parameter | Stackd | Flattr |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (2 ratings) — better |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | — | 2 — better |
| Update frequency | Every 4 days — better | Every 10 days |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad |
| Requires iOS | 15.1 — better | 17.6 |
| Further details — not scored | ||
| Size | 47 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Joshua Caplan | Ozgur Odabasi |
Customer experience
Stackd
Flattr
In-app purchases
Stackd
No in-app purchases
Flattr
No in-app purchases









