Replace Images / transparency

Hello,

I have already inserted/resized/positioned many images, and want them now to be brighter.

I’ve edited the images externally, but now need to replace the exiting ones with the new versions, but I wouldn’t want to do the insert/position/resize/position steps again. Is this possible?

Also, there are transparent parts in the PNG files, but I can’t see Scapple’s connection-lines (between the objects) through. Is this somehow possible?

Many thanks.