Keep pixels and profile together.
An image’s color profile tells compatible software how to interpret its pixel values. Changing or discarding that information can change the appearance. Correctly encoded pixels and the appropriate profile need to travel together.
Simply renaming a file does not alter its contents. Opening it in an editor and exporting again may. If you need to change the artwork, edit the original source and convert it again.
A screenshot is a different file.
Screenshot behavior varies by device and software. Some workflows preserve HDR; others make an SDR image or change the color information. A screenshot is therefore not a dependable way to transfer Glowhite’s export or demonstrate its brightness.
Use the downloaded JPEG itself. When sending it through a messaging or storage service, use an original-file option where available, then check the received file.
Find the point of change.
If the original looks brighter but the published copy does not, the platform may have transformed the file or may render its previews differently. Check the full-size asset as well as its thumbnail.
If neither version shows the extra brightness, revisit the browser and display setup. If the placement cannot reliably show the image as intended, publish the SDR original. Good artwork should survive the loss of the effect.