X hidden image not working? Fix tap-and-hold PNGs
Most failures come from re-encoding, a missing alpha channel or a different X rendition. Check these items in order.
Confirm the file is still PNG
Post the downloaded PNG directly. Screenshots and image editors can flatten transparency or convert the file to JPEG.
Post from X Web first
Mobile share sheets can re-encode images. Use x.com in a desktop browser for the first controlled test.
Keep the file below 5 MB
Smaller indexed PNGs are less likely to be replaced by another rendition. The maker reports format, dimensions and file size before download.
Test the feed and opened viewer
X Web, iOS and Android may show different renditions. Test light mode, dark mode and the full-screen viewer after publishing.