Transparent backgrounds in GPT Image 2: review the edges

The feature update

OpenAI added a transparent-background preview to GPT Image 2 on August 20, 2026. Transparent output uses PNG or WebP; JPEG does not preserve an alpha channel.

Check more than the empty background

A transparency test should inspect the silhouette, semi-transparent materials, soft shadows, and fine edges. Place the same result on light and dark backgrounds. A halo that is invisible on one surface can become obvious on another.

For a product asset, review whether the shadow belongs with the product or should be handled by the destination template. Make that choice part of the brief rather than correcting it differently for each image.

Keep alpha through the pipeline

Check the file after upload, resizing, optimization, and export. A downstream conversion can remove transparency even when the model response is correct. Retain an original asset so that a processing mistake does not require a new generation request.

Ask the publishing team to verify a sample in the actual destination. A browser preview alone does not establish that every content tool preserves the chosen format.

Treat preview behavior deliberately

Confirm current support for your exact model and endpoint before exposing the option to customers. Add a clear validation message when a selected output format cannot preserve transparency, and test the saved file rather than relying only on a successful response status.