Timeline card does not send subscription update when image is attached

[willjasen]

When a timeline card is sent to Glass with an image attached, the Update action does not send a subscription update that is received by the subscription callback URL. If a timecard card is sent excluding the image attachment, the subscription update works as expected.

[willjasen]

Changing the program so that the image is referenced by a link from Glass and isn't uploaded rendered the same old image over and over, though updates were working properly.