[donatj]

Would depend on what you're sending. If you take make good advantage of gif interframe transparency and are just sending small updates the result could be very small. That still leaves the problem unless I'm mistaken of the browser hanging on to the old gif frames.

[tcdent]

Are you saying that retention is bad from a memory use perspective, or that there is a risk of looping mid-broadcast?

[donatj]

Memory use. If it thinks it might finish and need to loop it would hold on to all the frames it's received.