What happens if my new image is a different size than the GIF?

It's automatically stretch-resized (nearest-neighbor) to match the GIF's existing canvas dimensions. This fills the frame completely but will distort the aspect ratio if it differs, which is documented, expected behavior rather than a bug.

Can I add more than one new frame at a time?

Yes, upload multiple images and they're inserted together, in the order you added them, at your chosen position.

Can I insert frames in the middle of the animation, not just at the start or end?

Yes, choose a specific 0-based index and the new frames are inserted immediately after that position in the existing sequence.

What delay do the new frames get?

You set a delay (in centiseconds) for the new frames before adding them; existing frames keep their own original delays untouched.

GIF Frame Adder - Insert New Frames Into a GIF

Overview

Introduction

Adding a new frame to an existing GIF usually means re-exporting the whole animation from scratch. This tool skips that: upload the GIF and one or more still images, choose where they go, and get back an animation with the new frames spliced in.

Everything happens locally in the browser via a hand-rolled GIF89a codec: nothing you upload is sent to a server.

What Is GIF Frame Adder?

A structural GIF editor that inserts new still-image frames into an existing animation at a chosen position, alongside the frames that were already there.

New frames are resized to match the GIF's existing canvas so the resulting file stays a single consistent size, as every valid GIF requires.

How GIF Frame Adder Works

The uploaded GIF is decoded into its frame array, and each new still image is loaded and, if its dimensions don't already match, stretch-resized with nearest-neighbor sampling to the GIF's width and height.

The resized new frames are spliced into the original frame array at the chosen position (start, end, or after a specific index), and the combined sequence is re-encoded as a fresh GIF89a file.

When To Use GIF Frame Adder

Use it to bookend an animation with a title card or an end-slate image without rebuilding the whole GIF.

It's also useful for inserting a still frame in the middle of a loop, for example to pause on an important beat.

Often used alongside GIF Joiner, GIF Frame Duplicator and GIF Frame Remover.

Features

Advantages

No need to re-export the entire animation just to add a frame or two.
Supports adding multiple new frames from separate image uploads in one pass.
Automatically resizes mismatched image dimensions rather than rejecting the upload outright.

Limitations

New frames are stretched to fit, not letterboxed/padded, so a very different aspect ratio will look distorted.
The combined GIF is capped at 256 total frames by this codec, matching the practical ceiling most GIF decoders support well.

Examples

Adding an end-slate frame

Input

5-frame looping GIF + one still "THE END" image, position: end, delay: 300cs

Output

A 6-frame GIF that plays the original loop, then holds on the end-slate for 3 seconds.

The still image is resized to match the GIF's canvas and appended as the final frame with its own delay.

Best Practices & Notes

Best Practices

Match your new image's aspect ratio to the GIF's canvas beforehand for the cleanest result, since stretching distorts mismatched ratios.
Pick a longer delay for a still "pause" frame than for the rest of the animation, so it reads clearly rather than flashing by.
Check the resulting frame count against the tool's 256-frame ceiling if you're adding many images at once.

Developer Notes

Resizing reuses the PNG category's shared `resizeNearest` helper rather than a bespoke resampler, keeping this category's image-manipulation math consistent with the rest of the codebase instead of re-deriving a second resize implementation.

GIF Frame Adder Use Cases

Adding a branded intro or outro frame to an existing animated GIF
Inserting a still "pause" frame partway through a looping animation
Building up a longer animation by combining several separately-created still images with an existing GIF

Common Mistakes

Uploading a new frame with a very different aspect ratio and being surprised it looks stretched rather than cropped or padded.
Forgetting to set a distinct delay for a new still frame, leaving it flashing by at the same short speed as the rest of the animation.

Tips

Use the GIF Frame Viewer afterward to confirm the new frames landed at the position you expected.
If you need to combine two full GIFs rather than a still image, use the GIF Joiner instead.

GIF Frame Adder