[Image-SIG] Distinguish single-frame from multi-frame GIF images?

[skip at pobox.com]

Is there a way to determine I'm dealing with a single-frame vs. multi-frame
GIF image without actually trying to seek?  For example, will the duration
key in the info dict always be present in multi-frame images (and never be
present in single-frame images)?

Thanks,

-- 
Skip Montanaro - skip at pobox.com - http://www.mojam.com/
"In China today, Bill Gates is Britney Spears.  In America today, Britney
Spears is Britney Spears - and that is our problem."  Thomas L. Friedman in
"The World is Flat"