The memory problem was alleviated some time after by rewriting the code for the ”soft CPU” (afaik this is the code for the minimal OS of sorts that runs on the ARM processor).
In any case, I don’t think it’s possible to do screenshots, in simple terms because there is no frame buffer. I suppose there is some theoretical possibility of saving from line buffer, but perhaps write speed sets some limitation. And I also think there is no file system (I may be wrong here). What needs to be kept in mind is that not all information from fpga side is necessarily easily retrievable at all times, unlike more traditional PC emulators.
I am not really technically versed, but I think this may be a case of ”had it been possible, it would have been implemented already”.