Image delivery / format check

Check PNG transparency and JPEG backgrounds

Use PNG when transparent pixels must remain. Use JPEG only after choosing an opaque background. Confirm the saved output and the destination separately.

Convert images locally

Choose the format and background

PNG may preserve an alpha channel. JPEG is opaque, so a transparent image becomes flattened against the background you choose.

Example	Observation	Decision	Reason
Transparent logo	PNG / alpha	Keep alpha	Let the destination show through
Photo on white	JPEG / opaque	Choose white	JPEG is enough for the delivery
Photo on dark	JPEG / opaque	Choose dark	Avoid an accidental white background
Icon export	PNG / alpha	Choose PNG	Preserve the transparency requirement
Photo export	JPEG / opaque	Choose background	JPEG cannot carry transparency
Unknown destination	Format/display unknown	Stop and verify	Do not guess rendering support

Review synthetic previews

Synthetic transparent preview on a checkerboard — The checkerboard illustrates transparent pixels; it does not prove destination rendering.

Synthetic opaque preview on a white background — White is an example of an intentional opaque background.

Check in this order

Decide whether the asset needs transparent pixels.
If yes, keep PNG alpha and do not export it as JPEG.
If no, choose the background color before saving JPEG.
Open the saved output and check the destination renderer and acceptance rules.
Stop until an unknown format or destination is confirmed.

This is a static browser-local guide. No real image, input or fixture is sent or stored externally.

What this does not guarantee

It does not make JPEG transparent, guarantee that a checkerboard preview matches a destination, or promise color management or acceptance. Check important deliveries in their target environment after saving.