Why this happens

Acoustic Campaign checks that every image inside your zip file is actually encoded in the format its file extension claims. If a file's extension doesn't match its real format — for example, a file named favicon.gif that's actually encoded as an ICO file — the upload fails with error IZE1002, even though the file looks fine in your file explorer.

Note: This isn't a restriction on GIF files specifically — GIF, JPG/JPEG, PNG, and ICO are all supported. The error means one file's actual format doesn't match its extension, not that its format is unsupported.

Find the mismatched file

1. Unzip your file locally and check each image, especially any favicon or small icon files — these are the most common culprits.
2. Open each image in an image viewer or check its properties/file info. Compare what the extension claims against what the tool reports the file actually is.
3. If you're not sure which file is causing it and support is involved, they may ask you to record a HAR file while you upload — that's a support-side diagnostic step, not something you need to do on your own.

Fix the file

Once you've found the mismatched file:

1. Rename its extension to match its actual format (for example, change favicon.gif to favicon.ico if the file is really an ICO).
2. If you need the file to stay in its original named format, re-export or re-save the image in that format instead, so the extension and the actual encoding match.
3. Re-zip your files and try the upload again.

Reference: supported image types

Tip: Remember your zip file can only contain HTML and image files — anything else will cause a different upload error. See Import HTML for the full list of zip requirements.

Next steps

• Import HTML
• Use images, animated GIFs, and videos in your emails
• Upload images, videos, and files