GIF Merger
Merge multiple GIFs into one — sequentially (append), side by side, or vertically stacked.
About GIF Merger
Merge multiple GIFs into one — sequentially (append), side by side, or vertically stacked.
Each GIF is decoded into composited frames, then either appended (sequence), placed side-by-side, or stacked vertically. Frames are re-encoded with a fresh per-frame palette for accurate colour reproduction.
Related tools
About GIF Merger
GIF Merger is a single-page tool for the common image editing and conversion task it is named after. Merge multiple GIFs into one — sequentially (append), side by side, or vertically stacked. The interface keeps the input on one side, the configurable options in the middle, and the result on the other side. Most jobs start and finish without any scrolling.
Typical users of GIF Merger include social-media managers sizing posts, students compiling visual reports and e-commerce owners cleaning product shots. The thread connecting all of them is the same: a focused image editing and conversion task that fits cleanly into a browser tab and benefits from a tool with sensible defaults and minimal setup.
GIF Merger parses your file with standard browser APIs entirely inside the browser, applies the options you selected, and returns a download. The processing has no network step, which means a slow or intermittent connection does not slow down the work — once the page is loaded, only your CPU and RAM are involved.
Technically, the work is done by standard browser APIs, loaded as part of the page. Inputs in GIF format are recognised automatically and validated before the engine begins processing. Files up to 50 MB are supported per run; that ceiling keeps browser memory usage stable on a wide range of devices.
GIF Merger works well as a bookmarked utility you reach for when you need it. The first visit shows you what the tool does; the second is when you realise it is a low-friction option for the task and worth keeping in your tab list.
Once you have used GIF Merger, the natural next steps depend on what you are doing with the result. Common follow-ups include GIF Splitter, Slideshow to GIF, and GIF Overlay. These are surfaced on the page so you do not have to hunt the catalog manually.
GIF Merger returns the result as `{name}-edited.gif`. If you are running multiple jobs, the output names will not collide as long as the input names differ. You can re-run with different settings as many times as you like; each run produces a fresh file with no caching trickery in between.
The 50 MB ceiling on input size is the only fixed limit. Output files are produced in standard formats that every common viewer recognises, and the tool runs the same way regardless of how many times you have used it during the session.
GIF Merger keeps the control set focused. Every option on the page is there because a real workflow needs it, and the defaults aim at the most common case so a first-time user can get the right output without changing any settings.
Some context on why GIF Merger exists in this form: modern File APIs, high-performance JavaScript engines, and well-maintained open-source libraries now make it possible to perform image editing and conversion work entirely in the browser. GIF Merger is built on top of that capability, which is why a single page can host the full pipeline.
If you want to get the most out of GIF Merger, three small habits help. Drag-and-drop is faster than the file picker once you get used to it. The keyboard shortcut for downloading the result is whatever your browser uses for "save link as," because the result is a normal download. And if you are working on a sensitive file, processing in an Incognito or Private window is a good extra layer — it leaves no trace in browser history when the tab closes.
Common gotchas worth flagging: GIF Merger only accepts GIF, so if your file is in another format you will need to convert it first. The 50 MB ceiling is per-file, not per-session; you can run as many separate jobs as you like, but a single oversized input will be rejected on load.
If you also use a command-line tool for gif merger, GIF Merger is a convenient alternative for the times you are on a different machine or helping someone who is not comfortable in a terminal. The output is a standard file in the format documented above.
GIF Merger is intentionally narrow in scope so the common case is fast and the result is predictable. If you ever need a variation it does not cover, browse the rest of the catalog — there is a good chance an adjacent tool already exists, and switching between tools is just a matter of opening another tab.
How it works
- 1Reach the GIF Merger page in your browser to begin.
- 2Drop a GIF file onto the upload area, or click to pick one from your device.
- 3Pick any non-default settings you need. Most users leave the defaults alone for the first run and only revisit if the result needs tuning.
- 4Trigger processing. standard browser APIs reads your input, applies the transformation, and writes the result back into the page.
- 5Download the result as `{name}-edited.gif`. The file is generated in your browser and saved through your normal download flow.
- 6Re-run with different settings as often as you want. Each run produces a fresh output and the original file on disk is never modified.
Common use cases
- Prepare a transparent logo for use over different backgrounds using GIF Merger.
- Resize a hero image for a landing page without losing crispness.
- Convert a batch of camera files into web-friendly formats.
- Strip EXIF data from a photo before posting it publicly.
- Crop an image down to the section you actually want to share.
- Optimise a product photo so it loads quickly on a slow connection.
- Apply a quick filter for a social-media post.
- Convert a phone screenshot into a CMS-friendly format.
FAQ
What merge modes are available?
Sequential (one after another), side by side (horizontal), and stacked (vertical).
What if GIFs have different sizes?
They are aligned according to your alignment setting (start, center, or end) and padded as needed.
What about different frame rates?
Each GIF keeps its original frame timing. In sequential mode, GIFs play one after another with their original speeds.
Maximum number of GIFs?
No hard limit, but merging many large GIFs increases file size and processing time.
Can I merge GIF with static images?
Upload images as well — they are treated as single-frame GIFs with the specified delay.
Private?
Yes — merging happens locally.
Why is in-browser GIF processing slower than online editors?
Server-side editors run on dedicated CPUs with native code paths and parallel workers. Our GIF engine decodes every frame with gifuct-js and re-encodes with gifenc — both pure JavaScript libraries running single-threaded inside your browser tab, which is typically 2–5× slower than a backend pipeline. The trade-off is total privacy: your GIF is never uploaded, never logged, never stored on any third-party server. Closing the tab erases everything from memory immediately. For most short loops the wait is small, and for sensitive material — work captures, dashboards, private screen recordings — the privacy gain is well worth the few extra seconds.
Is my GIF uploaded to a server?
No. Everything runs entirely inside your browser tab using gifuct-js for decoding, the HTML5 Canvas API for pixel work, and gifenc for re-encoding. The file is decoded into local memory only, processed in the same tab, and the result is offered as a direct download. Nothing is transmitted to any server, no account is required, no analytics are tied to your file, and closing the tab discards every byte from memory.
How big a GIF can I process?
Up to 50MB and roughly 16 megapixels per frame, with a soft cap of about 600 frames. The limit exists because every frame needs to fit inside your tab's memory as full-resolution RGBA pixels (four bytes per pixel). Most short loops, screen recordings, and reaction GIFs sit comfortably under that ceiling. If your GIF is larger, run the GIF Compressor or GIF Frame Skipper first to bring it down before applying further effects.
How are colours quantized in the output?
gifenc builds a fresh palette per frame using a wu-quant algorithm with up to 256 colours. This keeps colour-shifting effects (fades, glitch, brightness) accurate even when the source palette was tiny. You can lower the colour count in the Color Reducer / Compressor / Lossy Compressor tools to trade colour fidelity for smaller files.
Are transparent backgrounds preserved?
Yes — gifuct-js gives us a per-frame alpha channel from the original GIF's disposal data, and we composite frames into RGBA buffers so transparency survives every effect. When you re-encode, gifenc writes a 1-bit transparent palette index whenever the source alpha was zero, so transparent regions remain transparent in the output.
Does the loop count carry over?
Yes — when the source GIF declares a loop count via the NETSCAPE2.0 application extension, we read it during decoding and write the same value into the output container. If the source has no loop block (a one-shot GIF), the output also plays once. Tools that explicitly let you change loop behaviour (Loop Editor, Boomerang, Player) override this and write whatever loop count you choose.
Which browsers are supported?
Recent Chrome, Edge, Firefox, Safari, and other Chromium-based browsers all work. The tool only relies on the standard HTML5 Canvas API, ArrayBuffer, and Blob URLs, all of which have been universally supported for over a decade. Mobile browsers work too, although large GIFs may take noticeably longer because phone CPUs are weaker than desktop CPUs.
Is there a watermark or sign-up wall?
No. The tool is completely free, requires no account, attaches no watermark, and shows no popup ads on your output. A small fair-use throttle runs in the background to discourage automated abuse, but it does not affect normal one-off conversions. The downloaded GIF is exactly what gifenc wrote out from your edited frames — nothing more, nothing less.
Does GIF Merger match what professional tools produce?
GIF Merger is built on standard browser APIs, which is the same class of engine used by professional image editing and conversion pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
How accessible is the GIF Merger interface?
GIF Merger uses native HTML controls wherever possible, which means keyboard navigation, focus rings, and screen-reader labels work the way the platform expects. The drop zone accepts files via the keyboard-accessible file picker as well as drag-and-drop, and result downloads use standard browser download flows. If you spot an accessibility gap, Favtoo treats it as a bug worth fixing.
Is GIF Merger lossless?
GIF Merger is built to preserve quality wherever the underlying image format allows it. Operations that are mathematically lossless (e.g. structural transformations, lossless re-encoding) round-trip with no perceptible change. Operations that involve a lossy codec inevitably introduce small artefacts at the byte level, but the defaults aim at the sweet spot where output looks or sounds the same to a normal viewer or listener while still being meaningfully smaller or faster than the input.
Which file formats does GIF Merger accept?
GIF Merger accepts GIF. If your input is in a format that is not directly supported, convert it first using one of Favtoo's converter tools — every Favtoo converter outputs a file that is a clean input to the next tool in the chain.
Can I self-host GIF Merger for my team?
GIF Merger is a static page running an open-source engine in your browser, so a typical corporate firewall does not get in the way as long as it allows JavaScript to load from Favtoo. For teams that need to host it themselves on an internal network, the underlying engine (standard browser APIs) is open-source and can be packaged into a private build with the same behaviour. Reach out via the Contact page if that is something you are exploring.
Will GIF Merger ask me to pay to download the result?
GIF Merger is free to use. The processing runs in your browser, which keeps the per-user cost low enough that the tool can be offered openly. The download is the same file the engine produced — you can use it for as many runs as you need.
How long does GIF Merger take to process a file?
Most jobs finish in seconds. Speed scales with input size and with how many CPU cycles your browser tab has available — the engine runs in your browser, so it shares resources with whatever else you have open. For inputs near the 50 MB ceiling, expect anywhere from a few seconds to roughly a minute on a typical laptop. Closing other heavy tabs noticeably speeds things up.