The decoding property of the HTMLImageElement interface represents a hint given to the browser on how it should decode the image.


A string representing the decoding hint. Possible values are:

  • sync: Decode the image synchronously for atomic presentation with other content.
  • async: Decode the image asynchronously to reduce delay in presenting other content.
  • auto: Default mode, which indicates no preference for the decoding mode. The browser decides what is best for the user.

Usage notes

The decoding property allows you to control whether or not the browser is allowed to try to parallelize loading your image. If doing so would cause problems, you can specify sync to disable asynchronous loading. This can be useful when applied to <img> elements, but may be even more so when used for offscreen image objects.


var img = new Image();
img.decoding = 'sync';
img.src = 'img/logo.png';


HTML Standard
# dom-img-decoding

Browser compatibility

BCD tables only load in the browser