How to make a hidden image for X
Use two images to make one transparent PNG that changes with X’s light and dark backgrounds.
Choose a bright first image
The image shown before opening works best when it has bright tones, clear shapes and moderate detail.
- Use PNG, JPEG or WebP
- Avoid tiny text
- Start below 2048 px
Choose a darker hidden image
The revealed image should be darker than the first one. Strong silhouettes survive X re-encoding better than subtle texture.
Adjust and check all previews
Use hidden strength, brightness, contrast and crop controls. Check the light feed, opened viewer and dark feed previews.
Download and test on X
Upload the downloaded PNG directly. Do not edit it in another app first. Verify the published post on X Web, iOS and Android.