2288 x 1712 pixels? yeah.. you could say it's kinda big but too-big is common around here.
i see you have the chain tensioner..
get some bike chain and a link-tool and maybe a master link... find a steel rod for the pedal shaft.. It's diameter will probably be perfect for some bicycle pedal parts.. I think moped manufacturers do it deliberately and purchase their bicycle parts.
Find a small sprocket and weld that to the shaft.. File flats into the shaft's ends. (180 degrees from each other) and it's done..
That bike is almost complete.. It ran before it was in storage.. no reason to think it won't fire up again with a bit of work..and to me it looks like it's well worth the extra effort of rebuilding the pedals.
I might pay $50 or so for it the way it sits.. but since you offered it for $20..