Thanks Veeta. Adding the the puzzle is the fact that roPosterScreen does work for some HTTPS images. In my case some of the Instagram photos are hosted on a Akami CDN and those work fine (generally the user profile pics). It looks like the main photo content moved to a different CDN technology and they are the ones having the problem. Maybe a more complicated SSL handshake on one CDN vs. the other?
It looks like an HTTPS request using roPosterScreen, roSlideshow, etc. is only negotiated by the Roku to use TLS 1.0, whereas an HTTP request using roUrlTransfer negotiates the use of TLS 1.2. Due to security vulnerabilities discovered in older TLS versions, it's possible that some servers are refusing to allow connections that use the older versions, which might explain why one CDN (Akamai) works and the other one (Instagram) does not.
It would be helpful if someone from Roku could look into this and verify whether roPosterScreen, etc. erroneously only supports TLS 1.0.
Hi guys, I am also linking to my Instagram photos and recently found they wouldn't display in the slideshow anymore. Great to see others are working through this issue. This is a nasty bug, crippling even. Thanks for your valuable inputs AC