Modern Image Formats: The alternate mime type images didn't add original image extension in image name

[mukeshpanchal27]

Bug Description

While i doing smoke testing for plugin release i found that the uploaded image didn't add original image extension( -jpeg or -jpg ) in the full and sub-sizes image. For sub-size previously i reported #1560. After 6.7 the full size image also didn't get the image extension.

In #444 we added the original image's extension to the WebP file name to ensure it is unique but after 6.7 the original issue reintroduce.

Image.jpeg

<img
    fetchpriority="high"
    decoding="async"
    width="600"
    height="400"
    src="https://closebat.s1-tastewp.com/wp-content/uploads/2024/11/image.webp"
    alt=""
    class="wp-image-15"
    srcset="
        https://closebat.s1-tastewp.com/wp-content/uploads/2024/11/image.webp 600w,
        https://closebat.s1-tastewp.com/wp-content/uploads/2024/11/image-300x200.webp 300w
    "
    sizes="(max-width: 600px) 100vw, 600px"
>

Image.jpg

<img
    decoding="async"
    width="600"
    height="400"
    src="https://closebat.s1-tastewp.com/wp-content/uploads/2024/11/image-1.webp"
    alt=""
    class="wp-image-16"
    srcset="
        https://closebat.s1-tastewp.com/wp-content/uploads/2024/11/image-1.webp 600w,
        https://closebat.s1-tastewp.com/wp-content/uploads/2024/11/image-1-300x200.webp 300w
    "
    sizes="(max-width: 600px) 100vw, 600px"
>

Steps to reproduce

1. Install and activate Modern Image Formats plugin.
2. Upload two same name image. image.jpeg and image.jpg
3. See frontend.

Screenshots

[felixarntz]

@mukeshpanchal27 Have you verified where this comes from? I'm not sure if it's really a bug in our plugin or simply happens because Core handles MIME type changes in a different way.

This problem, does it only happen when you don't use fallback images, or only when you use fallback images, or in both scenarios? This would be great to specify.

[mukeshpanchal27]

This problem, does it only happen when you don't use fallback images, or only when you use fallback images, or in both scenarios? This would be great to specify.

It is only happened when don't use fallback images.

[felixarntz]

It is only happened when don't use fallback images.

In that case, I assume this is simply because Core is now handling the migration. To be fair, it already did before for images above the "big image threshold", so this isn't even entirely new behavior, we just never caught on to it, similar to #1634.

So I would say this is not truly a bug, but since per #444 not including the original file suffix in the file name could lead to problems, we should probably raise this upstream in Core, as I believe it should apply there too. Let's see if we can recreate the problem with Core alone.