Invalid File Warning When Using AVIF Images

Hello @drivenfaroff ,
Greetings. Hope you are doing well.

Thanks for reaching out to us and sharing the details with us. I have checked on my end with the Image Gallery Block plugin version 1.3.4 and found that the .avif format image is visible properly in the ligthbox. Please check this screencast from my end: https://d.pr/v/iNLGFQ

Also, I have used th Modern Image Formats plugin that you suggested and converted the image on upload into .avif format. I found that the images are visible properly. Please check this screencast: https://d.pr/v/INg6tO

Will you please tell me if is it being blocked by CORS or, Content-Security-Policy? Also, does the lightbox JS throw any errors? Please provide us the URL of the page where you are using this block and facing the issue so that we can check and assist you. In the meantime, I request you to use this .avif format image on any other block i.e Image and check if those show the image properly or, not.

Looking forward to hearing from you.
Thank you.