Hi thank you for your review and raising your concern. It could be that you found an avif image that is not yet supported by the Avif detection algorithm. Also in case you have installed other extensions there could be a chance that they would interfere with the conversion. Alternatively a webserver is simply serving jpg, png or another format image while wrongfully adding the .avif extension.

To be sure could you please verify you can see and convert the avif image on this page: https://libre-software.net/avif-test/ ? if not try resetting the addon and try again. If this image works and you can convert it please send the image or a link to the image you are trying to convert. Than I can analyze it and if nessecary update the algorithm.

Conversion to GIF and animations are currently not supported in this add-on. So for now you have to look for an alternative solution.

Thank you for taking the time to write a review. However this addon does not add the random information to the image you write about. From what you wrote it seems to me that you have the add-on "Save webP as PNG or JPEG (Converter)" installed (aswell) that does have this behavior but is unrelated to this add-on

It is not perfectly clear to me what you are doing. I assume that the pop up "save as" dialog is throttling your workflow. You can turn this popup off and download the converted image directly. Open the settings using the converters browser button at the top right of the browser. Than navigate to the "generic" tab and change to advanced mode. There you can turn off the save as dialog. Also make sure the filename conflict action is set to unique (default) if you want to avoid automatic overwriting existing files. Hopefully this resolves your issue if not please let me know and I might b able to help you further.