Problem 1: the image is HUGE. 4.6-ish megabytes and 2kx2k pixels. should be scaled down to at least biggest size that its ever reasonably shown at. otherwise users are spending time downloading pixels they cant see

Problem 2: found this that might be useful: https://developers.google.com/web/updates/2016/12/performant-parallaxing

images scaled down and jpegs optimized according to basically google's recommendations. see linked PR. Also feel free to add the other scroll optimizations to this PR
headshots reduced to a width of 250 (down from ~3000px)
bit by bot images reduced to a width of 500px (down from ~1500px)
recently added logo images reduced down to whatever maximum size they are displayed at on the site (800px wide for the big one, ~25 px tall for the small nav one)

Remember that doubling the width/height of a square image results in a quadrupling of the file size/number of pixels, and thus, the time it takes to download.