Bringing large images into Storyline

hi there,

Is it ok to bring images approx 1000 x 748 in size

at 300 dpi

into Storyline and resize/reduce on the canvas?

Is the manual resize function also reducing the weight/file size of the photo?

It appears to be automatically reducing the size when I check 'Size and Position' menu but is this effecting the actual file size?

Should I also  be adjusting the dpi to 72 before bringing into Storyline?

Thanks!