v1 doesn’t have any form of base64 encoded image content due to intrisinc limits on how much data can be stored in flow states. You’ll probably run into this if you attempt to do this yourself with network requests.
This may be something we can implement in v2, but we aren’t currently looking for v2 suggestions on the forums as it seems likely there will be a forum wipe or archival at some point prior to v2 launch. Please hold your v2 suggestions until after we open up a proper feedback mechanism for v2.