type

Image.Format

type Format =

| 'jpeg'

| 'png'

| 'webp'

| 'heic'

| 'avif'

| 'bmp'

| 'tiff'

| 'gif'

bmp/tiff/gif are decode-only — metadata().format may report them but there are no .bmp()/.tiff()/.gif() encoder methods. tiff decode rejects with error.code === "ERR_IMAGE_FORMAT_UNSUPPORTED" on Linux; gif decodes the first frame everywhere.