Adds an image to be used in the style. This API can also be used for updating an image. If the image \a id was already added, it gets replaced by the new image.
The image can be used in icon-image, fill-pattern, and line-pattern.
icon-image
fill-pattern
line-pattern
layout-symbol-icon-image
paint-line-line-pattern
paint-fill-fill-pattern
A string describing an error if the operation was not successful, empty otherwise.
Bitmap data of the image.
ID of the image.