Specifying size of electron window

[tlienart]

Hello & thanks for this package!

Is it / would it be possible to specify the size of the electron window when using electrondisplay(obj) (e.g. to match the size of a PNG)? I tried to find such an option in the code but couldn't seem to find one, maybe I didn't look at the right spot.

Thanks!

PS: small side question, is it possible to specify the object be centered in the electron window? (it seems to be top-left by default)