GIF analyzer, every frame explained.

A GIF analyzer opens a GIF file and tells you what is inside it: how many frames it has, how long each frame stays on screen, how long the whole GIF lasts, how fast it plays, how many times it loops, how each frame is cleared, which colours it uses and whether it carries bytes it does not need. This one reads the file's own blocks in your browser and changes nothing, so it is a safe way to find out why a GIF plays too slowly, too fast, only once or at a bigger size than it should be.

How to use the GIF analyzer

1. Drop a GIF on the box, click to choose one, or paste one. The report appears at once.
2. Read the cards at the top: Frames, Length, Frame rate, File size, Size, Loops, See-through and Colours. Warnings sit under them in plain words.
3. Look at the Frame delays graph. Each bar is one frame, as tall as its delay. Point at a bar to read it, or click it to see that frame.
4. Scroll the Every frame table for the full detail of each frame. Click Show all when the list is longer than 200 frames.
5. Use the arrow under any frame picture to save that frame as a PNG. Click Copy the report to paste the numbers into a message, or Download frames as CSV to open them in a spreadsheet.
6. Click Check another GIF to start again.

What each number means

Delays under 0.02 seconds

The GIF format counts time in hundredths of a second. A delay of 0 or 1 hundredth asks for the next frame almost at once, and browsers commonly show such a frame for 0.1 s instead. The GIF specification sets no minimum, so this is a habit of players and not a rule of the format. The analyzer marks these frames in amber and gives both lengths. Take a GIF of 10 frames that each carry a delay of 1 hundredth. The file adds up to 10 times 0.01, which is 0.1 s, but a browser that shows each frame for 0.1 s plays it for 10 times 0.1, which is 1 s. That is ten times slower than the file says. If you see this warning, set a real delay with the GIF speed changer.

Disposal methods

The GIF89a specification (checked 19 Oct 2026, w3.org) names four values. 0 means no disposal is specified, 1 means the graphic is left in place, 2 means the area is restored to the background colour, and 3 means the area is restored to what it was before. A frame with a see-through part often uses 2, so the old picture does not show through. If a GIF leaves trails behind moving objects, look for disposal 1 on frames that have see-through pixels.

Loops

The repeat count is not part of the GIF89a specification. It comes from an application extension that browsers read as a common habit. A count of 0 means forever. No loop block at all means the GIF plays once and stops on its last frame, which is why a GIF that "does not loop" is usually just missing the block. The Loops card tells you which case you have.

Bytes that do nothing

The last section adds up bytes the file spends without changing how it looks: comments, extra blocks that no player uses, data after the end marker, a colour table copied into a frame when the global one is identical, and frames that look exactly like the frame before. The total is lossless to remove. It will not shrink a large GIF by itself; for that, use the GIF compressor, which also changes the pixels.

Common problems

• It plays slower than the length says: check for the amber delay warning.
• It plays once: the Loops card says Plays once. Re-save it with a loop count.
• The frame pictures look different from what you expect: each picture is drawn with the frames before it already in place, as a browser would show it, so a frame that only stores a small patch still shows the whole picture.
• You need the frames as files: save them one by one here, or all at once with GIF to PNG.