It doens't require the image to be buffered, it works on streaming data.
That will make it extermely critical as to processor speed being sufficient, if you choose a '51 better go with SIlabs

Now, it's very possible that the 8051 family will not be up to the task, but without a means of calculating it I just don't know. I guess you get a feel for it eventually.</i.
i guess you will be coding it in a high level language, so why not code it up and stick it into a simulator. then, if a '51 is not up to snuff, not much is lost.

Erik