Put it into practice
- Switch the actual application to the desired appearance.
- Capture matching content and viewport in both modes.
- Choose contrasting mockup backgrounds for each version.
What this looks like
A light UI on a dark neutral background remains clearly separated from its frame.
A detail to keep clear
Do not recolor screenshots in a way that claims an unsupported product theme.
Using MockupX
MockupX accepts pasted, dropped and uploaded images. Screen capture depends on browser support and your permission. The phone-transfer flow uses a temporary upload session. Prepare your source image before decorating it: a frame cannot recover unreadable text or remove sensitive information for you.
Check the result
Keep the original screenshot, then review the exported file at the size where people will see it. Check the message, the visible interface and the final crop separately. For a handoff, record the destination and the approved file so another person can distinguish the final version from a draft.
References and further reading
Use the official references for format behavior and current destination requirements. The composition advice above is a practical design approach, not a promise of platform approval.
MDN image formats ↗