The ACF Image Select Field is broken as of 3.5.6
In what way is id broken? What is the error that you’re seeing? I just tested it and it seems to be working but more detail would help.
Hello John,
Apologies for the vagueness.
It’s a Front-end issue in Input.js in the add popup function, more specifically the get_field_key function which apparently doesn’t exist.

Thanks!
I just tested on front end and it’s working, but I don’t have the image crop add on installed. This might be an issue with the changes in ACF effecting that plugin. You might want to post an issue over there.
The reason is the removal of this function in assets/js/acf-input.js
get_field_key: function( $field ){
return this.get_data( $field, 'key' );
},
Is third party plugins supposed to depend on this function?
Anyways it might be worthwhile to keep it to retain compatibility.
We did not expect this to break in a minor update
I don’t know, there’s been a lot of changes to the JS lately. I’ll let Elliot know, maybe it’s still supposed to be there.
Hi guys
Thanks for the bug report.
I’ll add this JS function back in and release a new version today
Sorry for the issue